feat/refacto: add configs.lua, setup install

- configs.lua holds the `repositories` data
- install health moved to health.lua
- plugins loads _root.setup() on startup
- install and list command are available through vim
> use them with `:TSInstall lang` and `:TSInstallInfo`

plugin/nvim-treesitter.vim

@@ -4,6 +4,13 @@ if exists('g:loaded_nvim_treesitter')
   finish
 endif
 
+lua << EOF
+ts_installable_parsers = function()
+  return table.concat(require'nvim-treesitter'.available_parsers(), '\n')
+end
+require'nvim-treesitter'._root.setup()
+EOF
+
 let g:loaded_nvim_treesitter = 1
 
 augroup NvimTreesitter