[TASK] Rework how we solicate feedback

We have decided to no longer ask users to create GitHub issues for
feedback as this doesn't work well with how we work.

- drop the issue template for technical feedback
- in the README, link to GitHub discussions instead of issues

Fixes #1500

README.md

@@ -26,7 +26,7 @@ You can also use this extension to manage your collection of delicious teas.
 We value and welcome feedback of all kinds, including discussions.
 Feedback can be sent via TYPO3 slack within [our channel](https://app.slack.com/client/T024TUMLZ/CSQ8T0VS5) or via direct massages to the team members.
 We also welcome email. All the contact information is available at our [typo3.org team page](https://typo3.org/community/teams/best-practices).
-Another way is to open an [issue on GitHub](https://github.com/FriendsOfTYPO3/tea/issues/new/choose).
+Another way is to create a [discussion on GitHub](https://github.com/FriendsOfTYPO3/tea/discussions).
 
 ## Philosophies