Merge branch 'commit_template' into 'master'

Add shared commit template

See merge request openappstack/openappstack!513

.gitlab/commit_template.txt

+
+# Subject above, 50 chars max. 50 chars end here ↑
+# Description below:
+
+# Additional CI directives
+#
+# Include apps to install even there's no code change that would
+# trigger an atomated installation, i.e.:
+# TRIGGER_JOBS=enable-nextcloud
+#
+# or trigger all jobs:
+# TRIGGER_JOBS=enable-monitoring,enable-nextcloud,enable-rocketchat,enable-single-sign-on,enable-wekan,enable-wordpress
+#
+# Reference issue number with one of:
+#
+# Fixes: #
+# Closes: #
+# Related: #
+#
+# Install this commit template from git root with: `git config commit.template .gitlab/commit_template.txt`