Show alert count

Lets land this in the 3.0.x branch first.

yea lets add a config option for this.

- Merged 3.x into MR
- Added config option for 'Show alerts count'
- Added translation for @current_count of @total_count alerts
- Fixed db queries in a preprocess loop for total count by static caching it
- Added JS function updateAlertCount on initAlerts and removeAlert. Message is dynamic and translatable

Can you update MR for 3.0.x

Created new MR: https://git.drupalcode.org/project/sitewide_alert/-/merge_requests/66

Nice, lets add some test coverage for this.

Added tests, it is a FunctionalJavascriptTest. I wanted to test the alerts count change on adding new alert and dismissing another alert, and it kinda become also a test for sitewide_alert_block and refresh_interval. Hope you don't mind such a big test. Besides, there was no test cases for those things before, so it may be to the benefit

Also, a question maybe we may think of: should we hide alerts count when there is only one alert available for user? This also needs to be done via JS I believe, since dismissed alerts are in localStorage