Move lsp config to local file structure

.config/nvim/lsp/salt_ls.lua

@@ -0,0 +1,16 @@
+---@brief
+---
+--- Language server for Salt configuration files.
+--- https://github.com/dcermak/salt-lsp
+---
+--- The language server can be installed with `pip`:
+--- ```sh
+--- pip install salt-lsp
+--- ```
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'salt_lsp_server' },
+  filetypes = { 'sls' },
+  root_markers = { '.git' },
+}