Add :tools lsp checks for +lsp flag

Also:
- Reorganizes some :lang modules' packages.el file.
- Adds setuptools check in lang/python
- Adds javac check in lang/java
- Removes the depends-on! macro

modules/lang/java/doctor.el

@@ -0,0 +1,9 @@
+;; -*- lexical-binding: t; no-byte-compile: t; -*-
+;;; lang/java/doctor.el
+
+(assert! (or (not (featurep! +lsp))
+             (featurep! :tools lsp))
+         "This module requires (:tools lsp)")
+
+(unless (executable-find "javac")
+  (warn! "Couldn't find the javac executable, are you sure the JDK is installed?"))