feat(gradle): add gradle module (#4423)

* docs: document gradle module

* implement gradle module

* gradle-module: add test for wrapper properties case

* docs: improve gradle module documentation

* fix: fix gradle module wrapper properties test

* drop gradle executable strategy

* apply suggested stuff

* Fix config schema

src/configs/starship_root.rs

@@ -58,6 +58,7 @@ pub const PROMPT_ORDER: &[&str] = &[
     "elm",
     "erlang",
     "golang",
+    "gradle",
     "haskell",
     "haxe",
     "helm",