💥 Remove :feature category

:feature was a "catch-all" category. Many of its modules fit better in
other categories, so they've been moved:

- feature/debugger -> tools/debugger
- feature/evil -> editor/evil
- feature/eval -> tools/eval
- feature/lookup -> tools/lookup
- feature/snippets -> editor/snippets
- feature/file-templates -> editor/file-templates
- feature/workspaces -> ui/workspaces

More potential changes in the future:

- A new :term category for terminal emulation modules (eshell, term and
  vterm).
- A new :os category for modules dedicated to os-specific functionality.
  The :tools macos module would fit here, but so would modules for nixos
  and arch.
- A new :services category for web-service integration, like wakatime,
  twitter, elfeed, gist and pastebin services.

modules/editor/file-templates/templates/gitignore-mode/__

@@ -0,0 +1,24 @@
+.DS_Store
+.idea
+*.log
+tmp/
+
+`(let ((type-ignore (yas-choose-value '("(none)" "python" "ruby" "java" "js"))))
+    (string-join
+       (cond ((string= type-ignore "python")
+              '("*.py[cod]"
+                "*.egg"
+                "build"
+                "htmlcov"))
+             ((string= type-ignore "ruby")
+             '(".ruby-version"
+               ".bundle"
+               "vendor"
+               "Gemfile.lock"
+               "coverage"))
+             ((string= type-ignore "java")
+             '("*.class"
+               "build"))
+             ((string= type-ignore "js")
+             '("*.tern-port")))
+       "\n"))`