Revert "Add Pull Request template file to the MariaDB/server repository"

This reverts commit 17106c984b9649641068ddf108dcffd2c7773212.

.github/pull_request_template.md

@@ -1,50 +0,0 @@
-<!--
-Thank you for contributing to the MariaDB Server repository!
-
-You can help us review your changes faster by filling this template <3
-
-If you have any questions related to MariaDB or you just want to
-hang out and meet other community members, please join us on
-https://mariadb.zulipchat.com/ .
--->
-
-<!--
-If you've already identified a https://jira.mariadb.org/ issue
-that seems to track this bug/feature, please add its number below.
--->
-- [x] *The Jira issue number for this PR is: MDEV-_____*
-
-<!--
-An amazing description should answer some questions like:
-1. What problem is the patch trying to solve?
-2. If some output changed, what was it looking like before
-   the change and how it's looking with this patch applied
-3. Do you think this patch might introduce side-effects in
-   other parts of the server?
--->
-## Description
-TODO: fill description here
-
-## How can this PR be tested?
-TODO: fill steps to reproduce here, if applicable,
-      or remove the section
-
-<!--
-Tick one of the following boxes [x] to help us understand
-if the base branch for the PR is correct
--->
-## Basing the PR against the correct MariaDB version
-- [ ] *This is a new feature and the PR is based against the latest MariaDB development branch*
-- [ ] *This is a bug fix and the PR is based against the earliest branch in which the bug can be reproduced*
-
-<!--
-You might consider answering some questions like:
-1. Does this affect the on-disk format used by MariaDB?
-2. Does this change any behavior experienced by a user
-   who upgrades from a version prior to this patch?
-3. Would a user be able to start MariaDB on a datadir
-   created prior to your fix?
--->
-## Backward compatibility
-TODO: fill details here, if applicable, or remove the section
-