Move lsp config to local file structure

.config/nvim/lsp/psalm.lua

@@ -0,0 +1,15 @@
+---@brief
+---
+--- https://github.com/vimeo/psalm
+---
+--- Can be installed with composer.
+--- ```sh
+--- composer global require vimeo/psalm
+--- ```
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'psalm', '--language-server' },
+  filetypes = { 'php' },
+  root_markers = { 'psalm.xml', 'psalm.xml.dist' },
+}