support pagination and filters for listing flists

[rawdaGastan]

• we need to add pagination in fl-server list flists endpoint
• we need to add filters for the flists too

questions

• Does it make sense to use some small db (say sqlite) to track the flists instead of scanning the entire directory of all flists everytime ?

The db can be recreated from fs when/if needed but it will be way more efficient to hit the db for queries like what flists we have, what users, what flists for that user, etc.. than scanning the fs