💥 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/slim-mode/__

@@ -0,0 +1,17 @@
+doctype html
+html(lang="en")
+  head
+    meta charset="utf-8"
+    meta http-equiv="x-ua-compatible" content="ie=edge"
+
+    title ${1:Page Title}
+    meta name="description" content=""
+    meta name="viewport" content="width=device-width, initial-scale=1"
+
+    / link rel="apple-touch-icon" href="apple-touch-icon.png"
+
+    link rel="stylesheet" type="text/css" href="css/master.css"
+
+    script src="https://cdnjs.cloudflare.com/ajax/libs/modernizr/2.8.3/modernizr.min.js"
+  body
+    $0