Move lsp config to local file structure

.config/nvim/lsp/buck2.lua

@@ -0,0 +1,18 @@
+---@brief
+---
+--- https://github.com/facebook/buck2
+---
+--- Build system, successor to Buck
+---
+--- To better detect Buck2 project files, the following can be added:
+---
+--- ```
+--- vim.cmd [[ autocmd BufRead,BufNewFile *.bxl,BUCK,TARGETS set filetype=bzl ]]
+--- ```
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'buck2', 'lsp' },
+  filetypes = { 'bzl' },
+  root_markers = { '.buckconfig' },
+}