GitLab: Add "Feature Request" issue template.

Based on Peter Krempa's libvirt template, feature.md.

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
CC: Peter Krempa <pkrempa@redhat.com>
Message-Id: <20210607153155.1760158-3-jsnow@redhat.com>
Message-Id: <20210623102749.25686-6-alex.bennee@linaro.org>

.gitlab/issue_templates/feature_request.md

+<!--
+This is the upstream QEMU issue tracker.
+
+Please note that QEMU, like most open source projects, relies on
+contributors who have motivation, skills and available time to work on
+implementing particular features.
+
+Feature requests can be helpful for determining demand and interest, but
+they are not a guarantee that a contributor will volunteer to implement
+it. We welcome and encourage even draft patches to implement a feature
+be sent to the mailing list where it can be discussed and developed
+further by the community.
+
+Thank you for your interest in helping us to make QEMU better!
+-->
+
+## Goal
+<!-- Describe the final result you want to achieve. Avoid design specifics. -->
+
+
+## Technical details
+<!-- Describe technical details, design specifics, suggestions, versions, etc. -->
+
+
+## Additional information
+<!-- Patch or branch references, any other useful information -->
+
+<!--
+The line below ensures that proper tags are added to the issue.
+Please do not remove it.
+-->
+/label ~"kind::Feature Request"