templates for issues and PR added

.github/ISSUE_TEMPLATE/bug-report.yml

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+name: 🐛 Bug report
+description: Something is not working correctly.
+title: "🐛 <title>"
+body:
+  - type: markdown
+    attributes:
+      value: >-
+        **Thank you for wanting to report a bug for this project!**
+
+        ⚠
+        Verify first that your issue is not [already reported on GitHub](https://github.com/cda-tum/mqt-core/search?q=is%3Aissue&type=issues).
+
+        If you have general questions, please consider [starting a discussion](https://github.com/cda-tum/mqt-core/discussions).
+  - type: textarea
+    attributes:
+      label: Environment information
+      description: >-
+        Please provide information about your environment. For example, OS, C++ compiler, mqt.core version etc.
+      placeholder: |
+        - OS:
+        - C++ compiler:
+        - mqt.core version:
+        - Additional environment information:
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Description
+      description: A clear and concise description of what the bug is.
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Expected behavior
+      description: A clear and concise description of what you expected to happen.
+  - type: textarea
+    attributes:
+      label: How to Reproduce
+      description: Please provide steps to reproduce this bug.
+      placeholder: |
+        1. Get package from '...'
+        2. Then run '...'
+        3. An error occurs.
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/feature-request.yml

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+name: ✨ Feature request
+description: Suggest an idea
+title: "✨ <title>"
+body:
+  - type: markdown
+    attributes:
+      value: >
+        **Thank you for wanting to suggest a feature for this project!**
+
+        ⚠
+        Verify first that your idea is not [already requested on GitHub](https://github.com/cda-tum/mqt-core/search?q=is%3Aissue&type=issues).
+
+  - type: textarea
+    attributes:
+      label: What's the problem this feature will solve?
+      description: >-
+        What are you trying to do, that you are unable to achieve as it currently stands?
+      placeholder: >-
+        I'm trying to do X and I'm missing feature Y for this to be
+        easily achievable.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Describe the solution you'd like
+      description: >
+        Clear and concise description of what you want to happen.
+      placeholder: >-
+        When I do X, I want to achieve Y in a situation when Z.
+    validations:
+      required: true

.github/pull_request_template.md

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+## Description
+
+Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.
+
+Fixes #(issue) <!--- Replace (issue) with the issue number that is fixed by this pull request. -->
+
+## Checklist:
+
+<!---
+This checklist serves as a reminder of a couple of things that ensure your pull request will be merged swiftly.
+-->
+
+- [ ] The pull request only contains commits that are related to it.
+- [ ] I have added appropriate tests and documentation.
+- [ ] I have made sure that all CI jobs on GitHub pass.
+- [ ] The pull request introduces no new warnings and follows the project's style guidelines.