Support for EU cloud instance

# Problem

When deployed on Splunk Cloud or Splunk on-premises, the add-on fails to consume events from `bitwarden.eu` (European) cloud instance.

# Cause

The configuration generator `package/appserver/static/javascript/views/setup_page.js` determine if a server is a cloud instance by looking for an exact match for `https://bitwarden.com`, and ignore actual server host when generating the configuration:

```javascript
// Update script.conf
const isBitwardenCloud = serverUrl === "https://bitwarden.com" || serverUrl === "bitwarden.com";
const apiUrl = isBitwardenCloud ? "https://api.bitwarden.com" : serverUrl + "/api/";
const identityUrl = isBitwardenCloud ? "https://identity.bitwarden.com" : serverUrl + "/identity/";
```

# Temporary solution

Manually patch the generated configuration file `${SPLUNK_HOME}/etc/apps/bitwarden_event_logs/local/script.conf` from:

```
[config]
apiUrl = https://bitwarden.eu/api
identityUrl = https://bitwarden.eu/identity
```

To:

```
[config]
apiUrl = https://api.bitwarden.eu/
identityUrl = https://identity.bitwarden.eu/
```

I confirm I am collecting Bitwarden events as excepted after applying this patch.

## Proper solution

Patch the configuration generator `package/appserver/static/javascript/views/setup_page.js` as follow:
- Parse server URL as an `URL` object
- Support for non-US region (e.g. `bitwarden.eu`)
- Use server's `host` value when templating the configuration

Start in package/appserver/static/javascript/views/setup_page.js and inspect how serverUrl is parsed and used to generate script.conf. Verify the generated configuration for bitwarden.eu uses the regional API and identity hosts, while preserving the existing bitwarden.com behavior; review closed PRs 57 and 63 for prior attempts.

Written by the indexing model from the issue text.