chore: Add GitLab issue templates

.gitlab/issue_templates/bug-report.md

+---
+name: Bug Report
+about: Report a bug in the application
+---
+
+* **What is the current behavior?**
+<!-- Issues like "doesn't work" and then not providing information as to WHAT isn't working, may be closed without further comment.-->
+
+
+* **If the current behavior is a bug, please provide the steps to reproduce**
+<!-- providing steps to reproduce is vital in order to verify that it is indeed a bug in the software, and not just a misconfiguration on your part. It helps us track down the source of the problem. -->
+
+
+* **What is the expected behavior?**
+<!-- How is it supposed to work, but currently isn't? What's the expected outcome of what you are currently trying to do? -->
+
+
+* **Please tell us about your environment:**
+<!-- Failing to provide this information slows down reacting on your issue. Withholding this information may lead to us not being able to reproduce your problem to find the source of the problem. -->
+
+- Your Operating System:
+- Your Java version: 
+- Your version of this piece of software:
+- Your config file: <!-- Upload your config-file to https://gist.github.com/ --> 
+- Your latest log file: <!-- Upload your log-file to https://gist.github.com/ -->
+
+* **Other information** (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow, gitter, etc)
+

.gitlab/issue_templates/documentation-request.md

+---
+name: Documentation Request
+about: Request for documentation about a certain aspect of this piece of software
+---
+
+# Documentation Request
+
+<!-- Delete this line and everything below it, but read below first for information on what you should include -->
+Please include the following:
+
+ * Links to any existing documentation if it exists but is unclear.
+ * Information on what feature/aspect of this application needs updating / expansion.
+ * What you're currently trying to do with the application that has led you to require the given feature.
+ * Some background on what information you might like to see in the documentation.

.gitlab/issue_templates/feature-request.md

+---
+name: Feature Request
+about: Request a feature for this piece of software
+---
+
+* **What is the current behavior?**
+<!-- Issues like "doesn't work" and then not providing information as to WHAT isn't working, may be closed without further comment.-->
+
+* **What is the wanted/requested behavior?**
+<!-- How is it supposed to work, but currently isn't? What's the expected outcome of what you are currently trying to do? -->
+
+* **What are your reasons for making this feature request? Provide solid arguments on why I should start working on it.**

.gitlab/issue_templates/pull_request.md

+---
+name: Pull Request
+about: Pull request for a change / addition / fix you made to the repository.
+---
+
+* **Please check if the PR fulfills these requirements**
+- [ ] Docs have been added / updated (for bug fixes / features)
+- [ ] Commits follow conventional commits
+<!--
+- type: breaking  # Changes that break something makes something incompatible to ealier version
+release: major
+- type: build     # Changes that affect the build system or external dependencies
+release: patch
+- type: chore     # Other changes that don't modify src or test files
+release: false
+- type: ci        # Changes to our CI configuration files and scripts
+release: false
+- type: docs      # Documentation only changes
+release: false
+- type: feat      # A new feature
+release: minor
+- type: fix       # A bug fix
+release: patch
+- type: perf      # A code change that improves performance
+release: patch
+- type: refactor  # A code change that neither fixes a bug nor adds a feature
+release: false
+- type: revert    # Reverts a previous commit
+release: patch
+- type: style     # Changes that do not affect the meaning of the code
+release: false
+- type: test      # Adding missing tests or correcting existing tests
+release: false
+-->
+
+* **What kind of change does this PR introduce?** (Bug fix, feature, docs update, ...)
+
+
+
+* **What is the current behavior?** (You can also link to an open issue here)
+
+
+
+* **What is the new behavior (if this is a feature change)?**
+
+
+
+* **Does this PR introduce a breaking change?** (What changes might users need to make in their application due to this PR?)
+
+
+
+* **Other information**: