[eglot] Add support for eglot lsp client in emacs

- Update README
- Add eglot-specifics to cc, rs, py, hs
  removing unused lsp-mode packages when eglot is active
- Add eglot-specific bindings
- Add doctor warnings for debugger +lsp and +peek
- Add eglot-backed lookup-handlers
- Add flycheck checker using eglot for :checkers
  syntax users (using flycheck/flycheck#1676 and
  flycheck/flycheck#1592 discussion).
  This implementation is based on @marsam code, and uses recent
  Flycheck development in order to make the code smaller and
  easier to maintain.

modules/lang/python/packages.el

@@ -9,7 +9,7 @@
     (package! flycheck-cython :pin "ecc4454d35")))
 
 ;; LSP
-(when (featurep! +lsp)
+(when (and (featurep! +lsp) (not (featurep! :tools lsp +eglot)))
   (package! lsp-python-ms :pin "5d0c799099"))
 
 ;; Programming environment