Improve bug report template & add PR template

Signed-off-by: AnErrupTion <anerruption@disroot.org>

.github/pull_request_template.md

@@ -0,0 +1,11 @@
+## What are the changes about?
+
+_Replace this with a brief description of your changes_
+
+## What existing issue does this resolve?
+
+_Replace this with a reference to an existing issue, or N/A if there is none_
+
+## Pre-requisites
+
+- [ ] I have tested & confirmed the changes work locally