feat(extras): Enable project-specific plugin specs using local .lazy.lua (#2115)

* feat(extras): Enable project-specific plugin specs using .lazy.lua

* added a warning when extra lazyrc is not the last plugin spec

lua/lazyvim/plugins/extras/lazyrc.lua

@@ -0,0 +1,39 @@
+--[[
+Enable project-specific plugin specs.
+
+File .lazy.lua:
+  is read when present in the current working directory
+  should return a plugin spec
+  has to be manually trusted for each instance of the file
+
+This extra should be the last plugin spec added to lazy.nvim
+
+See:
+  :h 'exrc'
+  :h :trust
+--]]
+local filepath = vim.fn.fnamemodify(".lazy.lua", ":p")
+local file = vim.secure.read(filepath)
+if not file then
+  return {}
+end
+
+vim.api.nvim_create_autocmd("User", {
+  pattern = "VeryLazy",
+  once = true,
+  callback = function()
+    local Config = require("lazy.core.config")
+    local Util = require("lazyvim.util")
+    local lazyrc_idx = Util.plugin.extra_idx("lazyrc")
+
+    if lazyrc_idx and lazyrc_idx ~= #Config.spec.modules then
+      Util.warn({
+        "The `lazyrc` extra must be the last plugin spec added to **lazy.nvim**. ",
+        "",
+        "Add `{ import = 'lazyvim.plugins.extras.lazyrc' }` to file `config.lazy`. ",
+        "Do not use the `LazyExtras` command. ",
+      }, { title = "LazyVim", once = true })
+    end
+  end,
+})
+return loadstring(file)()