feat(fzf): provide pre configured custom fzf pickers

[leblocks]

closes #52

[leblocks]

TODO:

• add tests for populate_quickfix runs in a vim.schedule, hard to assert something
• cover utils for pickers in tests not much to cover for now
• add custom previewer for types
• add namespace picker (just for fun :D) on select will open all files in the same workspaces (not feasible, needs new realtion in db)
• add vimdoc for new pickers
• add failover in case if fzf is not installed
• add optional checkhealth for fzf module

[leblocks]

record a demo