SQLite: Split actor and comment filearchive updates to a separate file

On a fresh install, update.php will apply patch-editsummary-length.sql
even though it doesn't need to. But this partially wipes out the new schema from
tables.sql, and the omnibus comment and actor table patches don't detect
this, leading to filearchive missing the new fields.

Unlike the case with patch-add-3d.sql in I335cb8d9, here the patch does
make a change (if only a tiny one): fa_deleted_reason changes from TEXT
to BLOB.

Change-Id: I08047ff1207d471660365c0eb3faabc0b47746bb