Issue template form (#16349)

* Create issue template using new format

This issue template has been based off of the current issue creation workflow defined in the ISSUE_TEMPLATE.md file
This commit allows for that issue template (which is a legacy method of creating an issue) to be deleted

* Delete old issue template file

This commit deletes the old issue template file, as it is both legacy and replaced by ISSUE_TEMPLATE/issue.yaml

* Adjust file upload and remove code of conduct checkbox

* Block blank issue creation

* Update feedback

Removed most requirements
Updated prompt to include instruction to state whether using try.gitea.io
Added default value to Gitea version

* Create Feature Request issue form

* Update and rename issue.yaml to bug-report.yaml

* Enable blank issue creation

Co-authored-by: a1012112796 <1012112796@qq.com>

* Update config.yaml

* Remove default & placeholder from Gitea version

* Create issue template in .gitea directory

* Add relevant bug report message to feature request

* Adjust name to remove banner

There is a banner that tells you to create a config.yml when you already have a config.yaml
Renaming the file stops this from occurring.

* Add UI bug report form

* Remove unnecessary question

Co-authored-by: a1012112796 <1012112796@qq.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lauris BH <lauris@nix.lv>

.github/ISSUE_TEMPLATE/feature-request.yaml

@@ -0,0 +1,23 @@
+name: Feature Request
+description: Got an idea for a feature that Gitea doesn't have currently?  Submit your idea here!
+body:
+- type: markdown
+  attributes:
+    value: |
+      1. Please speak English, this is the language all maintainers can speak and write.
+      2. Please ask questions or configuration/deploy problems on our Discord
+         server (https://discord.gg/gitea) or forum (https://discourse.gitea.io).
+      3. Please take a moment to check that your feature hasn't already been suggested.
+- type: textarea
+  id: description
+  attributes:
+    label: Feature Description
+    placeholder: |
+      I think it would be great if Gitea had...
+  validations:
+    required: true
+- type: textarea
+  id: screenshots
+  attributes:
+    label: Screenshots
+    description: If you can, provide screenshots of an implementation on another site e.g. GitHub