feat(bitbake): add language-server-bitbake support (#3199)

Add default config for `language-server-bitbake`, the Yocto Project's
official language server for bit bake.

lua/lspconfig/server_configurations/bitbake_ls.lua

@@ -0,0 +1,27 @@
+local util = require 'lspconfig.util'
+
+return {
+  default_config = {
+    cmd = { 'language-server-bitbake', '--stdio' },
+    filetypes = { 'bitbake' },
+    root_dir = util.find_git_ancestor,
+    single_file_support = false,
+  },
+  docs = {
+    description = [[
+https://github.com/yoctoproject/vscode-bitbake/tree/staging/server
+https://www.npmjs.com/package/language-server-bitbake
+
+Official Bitbake Language Server for the Yocto Project.
+
+Can be installed from npm or github.
+
+```
+npm install -g language-server-bitbake
+```
+    ]],
+    default_config = {
+      root_dir = [[util.find_git_ancestor]],
+    },
+  },
+}