MM-27312 Allow uploading 10 files per post (#16235)

* Allow uploading 10 files per post

* Increase Post.Fileids column size to fit 10 files

* Add Post.Fileids column changes to DB v531

* Fix current_schema_version

Co-authored-by: Claudio Costa <cstcld91@gmail.com>

* Update store/sqlstore/upgrade.go

Co-authored-by: Claudio Costa <cstcld91@gmail.com>

* Fix schema version

Co-authored-by: Diogo Lima Nicolau <diogo.lima.nicolau@cern.ch>
Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>
Co-authored-by: Claudio Costa <cstcld91@gmail.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

scripts/mattermost-postgresql-5.0.sql

@@ -398,7 +398,7 @@ CREATE TABLE public.posts (
     props character varying(8000),
     hashtags character varying(1000),
     filenames character varying(4000),
-    fileids character varying(150),
+    fileids character varying(300),
     hasreactions boolean
 );