Reorder issue templates and automatically add labels (#18875)

* Reorder bug-report.yaml

* Add bug label on bug-report.yaml

* Add feature label on feature-request.yaml

* Reorder ui.bug-report.yaml

* Apply suggestions

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: zeripath <art27@cantab.net>

.github/ISSUE_TEMPLATE/feature-request.yaml

@@ -1,5 +1,6 @@
 name: Feature Request
 description: Got an idea for a feature that Gitea doesn't have currently?  Submit your idea here!
+labels: ["kind/feature", "kind/proposal"]
 body:
 - type: markdown
   attributes: