This PR adds a new section to the documentation to contain workarounds for running GtS on slow hardware. Right now it only contains a procedure on how to run migrations on a different database instance in case the original database is too slow to finish a database migration in a timely manner. Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4457 Co-authored-by: Daniël Franke <df@ponc.tech> Co-committed-by: Daniël Franke <df@ponc.tech>