gitea/models/activities
wxiaoguang 520eb57d76
Use a separate admin page to show global stats, remove `actions` stat ()
Before, Gitea shows the database table stats on the `admin dashboard`
page.

It has some problems:

* `count(*)` is quite heavy. If tables have many records, this blocks
loading the admin page blocks for a long time
* Some users had even reported issues that they can't visit their admin
page because this page causes blocking or `50x error (reverse proxy
timeout)`
* The `actions` stat is not useful. The table is simply too large. Does
it really matter if it contains 1,000,000 rows or 9,999,999 rows?
* The translation `admin.dashboard.statistic_info` is difficult to
maintain.

So, this PR uses a separate page to show the stats and removes the
`actions` stat.


![image](https://github.com/go-gitea/gitea/assets/2114189/babf7c61-b93b-4a62-bfaa-22983636427e)

## ⚠️ BREAKING

The `actions` Prometheus metrics collector has been removed for the
reasons mentioned beforehand.
Please do not rely on its output anymore.
..
action.go Use the type RefName for all the needed places and fix pull mirror sync bugs ()
action_list.go
action_test.go Refactor `setting.Database.UseXXX` to methods ()
main_test.go
notification.go
notification_test.go
repo_activity.go
statistic.go Use a separate admin page to show global stats, remove `actions` stat ()
user_heatmap.go Localize activity heatmap (except tooltip) ()
user_heatmap_test.go