feat: add issue template

Resolves https://kolaente.dev/vikunja/frontend/issues/2177

(cherry picked from commit 5442306b7cf2b1e2e68c57cb9b3a464c31565fe6)

.gitea/issue_template.md

@@ -0,0 +1,44 @@
+<!--
+
+Please fill out this issue template to report a bug.
+If you want to propose a new feature, please open a discussion thread in the forum: https://community.vikunja.io
+
+-->
+
+**Version information:**
+
+Frontend Version:
+API Version: 
+Browser and OS Version:
+
+**Steps to reproduce:**
+
+<!--
+Add clear steps to reproduce the bug. Provide screenshots where applicable.
+-->
+
+1. 
+2.
+...
+
+**Expected behavior:**
+
+<!--
+Describe what happened.
+-->
+
+
+
+**Actual behavior:**
+
+<!--
+Describe what happened instead.
+-->
+
+
+
+**Checklist:**
+
+* [ ] I have provided all required information
+* [ ] I am using the latest release or the latest unstable build
+* [ ] I was able to reproduce the bug on [try](https://try.vikunja.io)