Improve output in case of error

## Problem

Sometimes the sandbox fails but does not clearly indicates it so.
If the user is unfamiliar with sandbox, they may not realize that it did not start properly.

See for example:
* https://forum.algorand.org/t/error-in-example-build-with-python/6048/6?u=fabrice
* https://forum.algorand.org/t/sandbox-fails-to-complete-initialization-on-testnet-it-doesnt-even-try-to-fast-catchup-can-anybody-help/5800/3?u=fabrice

## Solution

Have something that catches errors systematically and display a clear error message at the end:

```
ERROR: Something went wrong. Please look at sandbox.log and read https://github.com/algorand/sandbox#errors
```
(in case `-v` is not provided)

```
ERROR: Something went wrong. Please look at the error above and read https://github.com/algorand/sandbox#errors
```
(in case `-v` is provided)

where https://github.com/algorand/sandbox#errors is extended to give usual ways of fixing errors, including:
* check you are on the latest version (git ...)
* check that nothing is listening on ...
* reset the sandbox (warning clear up everything)
* reset Docker

See https://medium.com/@dirk.avery/the-bash-trap-trap-ce6083f36700 on how to trap errors.

## Dependencies

## Urgency