[GITEA] Use join for the deleting issue actions query

- The action tables can become very large as it's a dumpster for every
action that an user does on an repository.
- The following query: `DELETE FROM action WHERE comment_id IN (SELECT id FROM comment WHERE
issue_id=?)` is not using indexes for `comment_id` and is instead using
an full table scan by MariaDB.
- Rewriting the query to use an JOIN will allow MariaDB to use the
index.
- More information: https://codeberg.org/Codeberg-Infrastructure/techstack-support/issues/9

(cherry picked from commit 6646fcf31f)

Conflicts:
	tests/integration/api_nodeinfo_test.go
	https://codeberg.org/forgejo/forgejo/pulls/1178
(cherry picked from commit 6465b74632)

tests/integration/api_nodeinfo_test.go

@@ -33,6 +33,6 @@ func TestNodeinfo(t *testing.T) {
 		assert.Equal(t, "gitea", nodeinfo.Software.Name)
 		assert.Equal(t, 25, nodeinfo.Usage.Users.Total)
 		assert.Equal(t, 19, nodeinfo.Usage.LocalPosts)
-		assert.Equal(t, 2, nodeinfo.Usage.LocalComments)
+		assert.Equal(t, 3, nodeinfo.Usage.LocalComments)
 	})
 }