Add issue templates

Author: Mordil

.gitlab/issue_templates/Bug.md

@@ -0,0 +1,23 @@
+### Expected behavior
+_[what you expected to happen]_
+
+### Actual behavior
+_[what actually happened]_
+
+### Steps to reproduce
+
+1. ...
+2. ...
+
+### If possible, minimal yet complete reproducing code (or URL to code)
+
+_[anything to help us reproducing the issue]_
+
+### RediStack version/commit hash
+_[the RediStack tag/commit hash]_
+
+### Swift Version (output of `swift --version`)
+_[the output]_
+
+### OS version (output of `uname -a`)
+_[the output]_

.gitlab/issue_templates/Feature.md

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+## Problem Statement
+_[a short description of the problem that this solution will fix]_
+
+## Proposed Solution
+_[provide details of what you think this feature should look like]_
+
+## Alternatives
+_[outline alternative designs, or alternative solutions to still accomplish the stated goal]_