Summary:
Add `./bin/celerity sprites`, to replace script `./scripts/celerity/generate_sprites.php`.
Also make new workflow run `./bin/celerity map` at the same time.
Fixes T15437.
Test Plan: Changes a file that goes in the sprites, run new command
Reviewers: O1 Blessed Committers, speck
Reviewed By: O1 Blessed Committers, speck
Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Maniphest Tasks: T15437
Differential Revision: https://we.phorge.it/D25274
cb938d869c