Adds 3 Easter alts (Catria, Florina and Aella) to the online game. *Someone else* also returns for a little while to celebrate...!

This commits starts the SPNatI Valentine's Event

Include testing and offline characters offline; install a version of config.xml without those to production.

Move layer and epilogue icons to img/ and hide player images instead of setting their src to opponents/blank.png. Why use blank images.

Move ALL opponents (except the re-skins) into opponents/. Include all opponents in listing.xml, giving unofficial opponents status attributes.

Official and testing opponents are included in deployment by way of a python script. Only official opponents will be included on the individual select screen, unless additional status classes are listed in config.xml (e.g. <include-status>offline</include-status><include-status>testing</include-status>).

This simplifies status changes since directories don't have to be moved around and we don't have to specify full paths in listing.xml. It also simplifies code since we don't have to extract the opponent id from the folder path.

Unlocked epilogues will also work with offline/incomplete opponents, and stay unlocked if/when those are moved to official status.

The build should only deploy the necessary files and not anything
extraneous.

If this works, hopefully someone can tighten up my clumsy code.

I previously meant to change the line to the following with an asterisk:
- rsync -avz --exclude 'saves/*.txt' * .public
However, maybe this is a simpler but less direct way of doing things.

The current total size of our artifacts is over 1GB. By ignoring certain
files for spnati.net web hosting, I hope to reduce this back below 1GB.

The old line in .gitlab-ci.yml wanted to copy all files (including
subfolders) to ".public". The new line aims to copy all files (including
subfolders) to ".public", except for the "saves" folder (48MB) and all
txt files (15MB). I apologize if this does not work as intended!

I have also moved the Mei directory including images to the "saves"
folder, as she is not currently in the game.