Fix treesitter setup and Mason

[mbergo]

Lua package

Apply the Neovim config fixes for current plugin APIs:
replace deprecated nvim-treesitter install call with configs.setup

Errors on Debian:

                                                                             
                                                                                           
  /home/mbergo/.config/nvim/init.lua:856: attempt to call field 'install' (a nil 
  value)                                                                         
            
                                                                                 
                                                                                 
            
  # stacktrace:                                                                  
                                                                                 
            
    - .config/nvim/init.lua:856 _in_ **config**                                  
                                                                                 
            
    - .config/nvim/init.lua:257"

and

❯ Error executing vim.schedule lua callback: 
  ...l/share/nvim/lazy/mason.nvim/lua/mason
  -registry/init.lua:32: Cannot find package "lua_ls".                           
       
  stack traceback:                                                               
       
          [C]: in function 'error'                                               
       
          ...l/share/nvim/lazy/mason.nvim/lua/mason-registry/init.lua:32: in 
  function 
  'get_package'                                                                  
       
          ...on-tool-installer.nvim/lua/mason-tool-installer/init.lua:269: in 
  function
   'callback'                                                                    
       
          ...l/share/nvim/lazy/mason.nvim/lua/mason-registry/init.lua:153: in 
  function
   'refresh'                                                                     
       
          ...on-tool-installer.nvim/lua/mason-tool-installer/init.lua:345: in 
  function
   ''                                                                            
       
          vim/_editor.lua: in function ''                                        
       
          vim/_editor.lua: in function <vim/_editor.lua:0>

@tjdevries, big fan, my friend.