Use all media server sources for composition

[jtojnar]

Currently, we have our mediacache set up so it uses the files it captured and only fall back to files from icer.ink when there we do not have it:

https://github.com/jtojnar/nixfiles/blob/1817be7899538746d68fc28463f4f60ca1653d7c/hosts/azazel/fan-club-penguin.cz/mediacache/default.nix#L17

On the other hand, the compositor can only read a single directory so it will only be able to use a subset of files:

https://github.com/jtojnar/nixfiles/blob/29d6c3d122ddc7f35bf8935aa6461e8eca365392/hosts/azazel/fan-club-penguin.cz/pechar/default.nix#L57

Compare the composed image with the preview of this outfit:

https://pechar.fan-club-penguin.cz/#%7B%221%22%3A1%2C%222%22%3A%221985%22%2C%223%22%3A0%2C%224%22%3A0%2C%225%22%3A%22269%22%2C%226%22%3A0%2C%227%22%3A0%2C%228%22%3A0%2C%229%22%3A0%7D

Possible solutions

• Just merge the two directories
  • I would like to retain some metadata about who fetched it
  • There are also files that differ (even visually)
• Allow setting multiple directories in MEDIA_SERVER_LOCAL_DIRECTORY variable
• Fetch the files for composition over HTTP so that the merge is handled by nginx.
  • not sure about performance but it probably will not be that bad.