Adding vim.LSP integration

[JBenda]

vim.lsp.buf..list_workspace_folders()[1] returns nil if no LSP root is set and else the root directory.
May this can be used if NeoRootChangeDirectory gets an empty string, I find after multiple days of testing that this is a nice default.

[nyngwang]

@JBenda: Thanks for your issue! I'm busy with a new idea recently, so this will probably be a long-term one. Feel free to add more context since I know very little about LSP things...