add Feedback.md GitLab issue template

Signed-off-by: Kevin Morris <kevr@0cost.org>

.gitlab/issue_templates/Feedback.md

+**NOTE:** This issue template is only applicable to FastAPI implementations
+in the code-base, which only exists within the `pu` branch. If you wish to
+file an issue for the current PHP implementation of aurweb, please file a
+standard issue prefixed with `[Bug]` or `[Feature]`.
+
+
+**Checklist**
+
+- [ ] I have prefixed the issue title with `[Feedback]` along with a message
+      pointing to the route or feature tested.
+    - Example: `[Feedback] /packages/{name}`
+- [ ] I have completed the [Changes](#changes) section.
+- [ ] I have completed the [Bugs](#bugs) section.
+- [ ] I have completed the [Improvements](#improvements) section.
+- [ ] I have completed the [Summary](#summary) section.
+
+### Changes
+
+Please describe changes in user experience when compared to the PHP
+implementation. This section can actually hold a lot of info if you
+are up for it -- changes in routes, HTML rendering, back-end behavior,
+etc.
+
+If you cannot see any changes from your standpoint, include a short
+statement about that fact.
+
+### Bugs
+
+Please describe any bugs you've experienced while testing the route
+pertaining to this issue. A "perfect" bug report would include your
+specific experience, what you expected to occur, and what happened
+otherwise. If you can, please include output of `docker-compose logs fastapi`
+with your report; especially if any unintended exceptions occurred.
+
+### Improvements
+
+If you've experienced improvements in the route when compared to PHP,
+please do include those here. We'd like to know if users are noticing
+these improvements and how they feel about them.
+
+There are multiple routes with no improvements. For these, just include
+a short sentence about the fact that you've experienced none.
+
+### Summary
+
+First: If you've gotten here and completed the [Changes](#changes),
+[Bugs](#bugs), and [Improvements](#improvements) sections, we'd like
+to thank you very much for your contribution and willingness to test.
+We are not a company, and we are not a large team; any bit of assistance
+here helps the project astronomically and moves us closer toward a
+new release.
+
+That being said: please include an overall summary of your experience
+and how you felt about the current implementation which you're testing
+in comparison with PHP (current aur.archlinux.org, or https://localhost:8443
+through docker).