Add `filter_limit` parameter to API requests to retrieve all sites

**Description:**
Currently, the Matomo API request in the module is apparently limited to 100 entries by default. As a result, Drupal can only access the first 100 sites. The only workaround without modifying the code is to create another account with a separate auth token to fetch the next batch.

To fix this, the API request should include the `filter_limit` parameter. Setting it to a high number or `-1` would allow retrieving all sites. Ideally, this should be configurable in the module settings.

**Proposed Solution:**
- Add `filter_limit` to the API request.
- Make it configurable in the module settings to allow customization.

**Expected Outcome:**
Drupal should be able to fetch all sites without requiring multiple accounts.