feat: add logic to store data by native code (#130)

* refactor: make logic for Database be abstract
* feat: add logic for DB by string.dump
* fix: run with async.void to run synchronously
* test: add tests for native feature
* feat!: sort candidates by path when score is same
  This is needed because candidates from SQLite is sorted by id, but ones from native is sorted by path.
* chore: clean up types
* feat: add lock/unlock feature to access DB
* test: use async version of busted
  And disable benchmark tests (fix later)
* test: add tests for file_lock
* chore: use more explicit names
* chore: use plenary.log instead
* fix: wait async functions definitely
* feat: add migrator
* chore: fix logging
* fix: detect emptiness of the table
* fix: deal with buffer with no names
* test: loosen the condition temporarily
* test: add tests for migrator
* fix: return true when the table is not empty
* feat: load sqlite lazily not to require in start
* chore: add logging to calculate time for fetching
* feat: add converter from native code to SQLite
* feat: warn when sqlite.lua is not available
* feat: add FrecencyMigrateDB to migrate DB
* docs: add note for native code logic
* test: ignore type bug

lua/telescope/_extensions/frecency.lua

@@ -1,12 +1,13 @@
 local frecency = require "frecency"
+local sqlite = require "frecency.sqlite"
 
 return require("telescope").register_extension {
   setup = frecency.setup,
   health = function()
-    if vim.F.npcall(require, "sqlite") then
+    if sqlite.can_use then
       vim.health.ok "sqlite.lua installed."
     else
-      vim.health.error "sqlite.lua is required for telescope-frecency.nvim to work."
+      vim.health.info "sqlite.lua is required when use_sqlite = true"
     end
     if vim.F.npcall(require, "nvim-web-devicons") then
       vim.health.ok "nvim-web-devicons installed."