Small issues with `prerun.py`

## Overview

While testing out creation of a custom CKAN 2.10 image, I found some issues with [`ckan-2.10/base/setup/prerun.py`](https://github.com/ckan/ckan-docker-base/blob/main/ckan-2.10/base/setup/prerun.py). At a quick glance, these issues also affect the [CKAN 2.9 version of the file](https://github.com/ckan/ckan-docker-base/blob/main/ckan-2.9/base/setup/prerun.py).

## Issue: `TypeError` can be raised in `except subprocess.CalledProcessError` blocks

In both [`init_db()`](https://github.com/ckan/ckan-docker-base/blob/main/ckan-2.10/base/setup/prerun.py#L103) and [`init_datastore_db()`](https://github.com/ckan/ckan-docker-base/blob/main/ckan-2.10/base/setup/prerun.py#L147), the following logic occurs:

```python
except subprocess.CalledProcessError as e:
if "OperationalError" in e.output:
# (...)
```

If this `except` block is encountered, then the script will fail with a `TypeError` because the type of `e.output` is `bytes`, not `str`.

### Demonstration

Using the [`ckan/ckan-docker`](https://github.com/ckan/ckan-docker) setup, I modified `prerun.py` in the following way, to make the `db_command` inside `init_db()` invalid:

```python
def init_db():

db_command = ["ckan", "-c", ckan_ini, "db", "init3335"]
```

When I started the Docker containers, the script failed with a `TypeError`:

```text
[prerun] Initializing or upgrading db - start
Traceback (most recent call last):
File "/srv/app/prerun.py", line 100, in init_db
subprocess.check_output(db_command, stderr=subprocess.STDOUT)
File "/usr/lib/python3.10/subprocess.py", line 421, in check_output
return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
File "/usr/lib/python3.10/subprocess.py", line 526, in run
raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['ckan', '-c', '/srv/app/ckan.ini', 'db', 'init3335']' returned non-zero exit status 2.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/srv/app/prerun.py", line 206, in
init_db()
File "/srv/app/prerun.py", line 103, in init_db
if "OperationalError" in e.output:
TypeError: a bytes-like object is required, not 'str'
```

### Suggested Fix

There are multiple ways that this could be addressed. One option is to modify the invocations of `subprocess.Popen` and `subprocess.check_output` to explicitly open the output stream in text mode. Based on how `e.output` is used, I think that this is probably what is intended. Per the [official documentation for `subprocess`](https://docs.python.org/3/library/subprocess.html):

> If _encoding_ or _errors_ are specified, or _text_ is true, file objects for stdin, stdout and stderr are opened in text mode using the specified _encoding_ and _errors_ or the `io.TextIOWrapper` default. The *universal_newlines* argument is equivalent to _text_ and is provided for backwards compatibility. By default, file objects are opened in binary mode.

To demonstrate, I implemented this change by adding `text=True` inside the `subprocess.check_output()` call:

```python
def init_db():

db_command = ["ckan", "-c", ckan_ini, "db", "init3335"]
print("[prerun] Initializing or upgrading db - start")
try:
subprocess.check_output(db_command, stderr=subprocess.STDOUT, text=True)
```

Here are the results -- the `TypeError` does not happen anymore.

```text
[prerun] Initializing or upgrading db - start
2023-09-05 18:51:14,168 INFO [ckan.cli] Using configuration file /srv/app/ckan.ini
2023-09-05 18:51:14,168 INFO [ckan.config.environment] Loading static files from public
2023-09-05 18:51:14,389 INFO [ckan.config.environment] Loading templates from /srv/app/src/ckan/ckan/templates
2023-09-05 18:51:14,740 WARNI [ckanext.reclineview.plugin] The Recline-based views are deprecated andwill be removed in future versions
2023-09-05 18:51:14,766 INFO [ckan.config.environment] Loading templates from /srv/app/src/ckan/ckan/templates
2023-09-05 18:51:15,828 WARNI [ckan.config.middleware.flask_app] Extensions are excluded from CSRF protection! We allow extensions to run without CSRF protection but it will be forced future releases. Read the documentation for more information on how to add CSRF protection to your extension.
Usage: ckan db [OPTIONS] COMMAND [ARGS]...
Try 'ckan db --help' for help.

Error: No such command 'init3335'.

Traceback (most recent call last):
File "/srv/app/prerun.py", line 206, in
init_db()
File "/srv/app/prerun.py", line 110, in init_db
raise e
File "/srv/app/prerun.py", line 100, in init_db
subprocess.check_output(db_command, stderr=subprocess.STDOUT, text=True)
File "/usr/lib/python3.10/subprocess.py", line 421, in check_output
return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
File "/usr/lib/python3.10/subprocess.py", line 526, in run
raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['ckan', '-c', '/srv/app/ckan.ini', 'db', 'init3335']' returned non-zero exit status 2.
```

It looks like `text` was added in Python 3.7, which is the minimum supported version for CKAN, so adding that flag should be a reasonable thing to do.

### Final Note

As a final note, the documentation on [`subprocess` Exceptions](https://docs.python.org/3/library/subprocess.html#exceptions) and the [`subprocess.CalledProcessError` docs](https://docs.python.org/3/library/subprocess.html#subprocess.CalledProcessError) both seem to suggest that `subprocess.Popen()` will not raise a `CalledProcessError`, so it is possible that the `except subprocess.CalledProcessError` block in `init_database_db()` is actually unnecessary (or needs to catch a different Exception).

## Issue: Unnecessary import of `re` inside `check_solr_connection()`

There is an [unnecessary import of `re`](https://github.com/ckan/ckan-docker-base/blob/main/ckan-2.10/base/setup/prerun.py#L86) in an `except` block inside `check_solr_connection()`.

There is also a lot of unnecessary trailing whitespace on the lines in that same `except` block.

Start with ckan-2.10/base/setup/prerun.py and compare the corresponding ckan-2.9/base/setup/prerun.py, focusing on check_solr_connection(), init_db(), and init_datastore_db(). Review the subprocess calls and exception handling first; done means the reported TypeError path and the unnecessary re import and trailing whitespace are addressed consistently in both versions.

Written by the indexing model from the issue text.