Add Firefly III srvapp

[azukaar]

Seems good, there's just a thing: since 0.11, there's a new label to tell Cosmos what env vrar are persistent; it's useful so that you dont accidentally lose your password and stuff making your volumes unusable and stuff:

Here's an example, needs to be on both containers:

https://github.com/azukaar/cosmos-servapps-official/blob/master/servapps/Nextcloud/cosmos-compose.json#L30

[jwr1]

Should be good now.

[azukaar]

Perfect, awesome thanks!