Replace issue templates to use issue forms (#9772)

* Replace issue templates to use issue forms

This adds new GitHub issue templates based on forms to help contributors
provide the right information when creating a new issue. This aligns
with our internal templates for easier parsing.

* Update .github/ISSUE_TEMPLATE/2-bug-report.yml

Co-authored-by: Charles Korn <charleskorn@users.noreply.github.com>

* Apply PR feedback

---------

Co-authored-by: Charles Korn <charleskorn@users.noreply.github.com>

.github/ISSUE_TEMPLATE/1-feature-request.yml

@@ -0,0 +1,66 @@
+name: Feature request
+description: Submit a new idea
+title: "Idea: "
+labels: ["enhancement"]
+body:
+- type: textarea
+  id: what
+  attributes:
+    label: What is the problem you are trying to solve?
+    placeholder: A clear and concise description of what the problem is.
+  validations:
+    required: true
+
+- type: textarea
+  id: how
+  attributes:
+    label: Which solution do you envision (roughly)?
+    placeholder: Once the work is started, a design doc would be great!
+  validations:
+    required: true
+
+- type: textarea
+  id: alternatives
+  attributes:
+    label: Have you considered any alternatives?
+    placeholder: A clear and concise description of any alternative solutions or features you've considered.
+  validations:
+    required: false
+
+- type: textarea
+  id: context
+  attributes:
+    label: Any additional context to share?
+    placeholder: Add any other context or screenshots about the feature request here.
+  validations:
+    required: false
+
+- type: dropdown
+  id: size
+  attributes:
+    label: How long do you think this would take to be developed?
+    options:
+      - Small (<= 1 month dev)
+      - Medium (~2 months dev)
+      - Large (~3 months dev)
+      - X-Large (>4 dev)
+      - Not sure
+    default: 4
+
+- type: input
+  id: docs
+  attributes:
+    label: What are the documentation dependencies?
+    placeholder: Any docs to update?
+  validations:
+    required: false
+
+- type: input
+  id: proposer
+  attributes:
+    label: Proposer?
+    placeholder: Who proposed this if not you, the author of the issue?
+  validations:
+    required: false
+
+

.github/ISSUE_TEMPLATE/2-bug-report.yml

@@ -0,0 +1,44 @@
+name: Bug report
+description: Report a bug
+title: "Bug: "
+labels: ["bug"]
+body:
+- type: textarea
+  id: what
+  attributes:
+    label: What is the bug?
+    placeholder: A clear and concise description of what the bug is.
+  validations:
+    required: true
+
+- type: textarea
+  id: how
+  attributes:
+    label: How to reproduce it?
+    placeholder: Steps to reproduce the behavior. 1. Start Mimir (SHA or version) 2. Perform operations (Read/Write/Others)...
+  validations:
+    required: true
+
+- type: textarea
+  id: expectations
+  attributes:
+    label: What did you think would happen?
+    placeholder: A clear and concise description of what you expected to happen.
+  validations:
+    required: true
+
+- type: textarea
+  id: environment
+  attributes:
+    label: What was your environment?
+    placeholder: Infrastructure (e.g., Kubernetes, bare-metal, laptop), deployment tool (e.g., helm, jsonnet)
+  validations:
+    required: true
+
+- type: textarea
+  id: context
+  attributes:
+    label: Any additional context to share?
+    placeholder: Add any other context or screenshots about the feature request here.
+  validations:
+    required: false

.github/ISSUE_TEMPLATE/3-documentation-request.yml

@@ -0,0 +1,45 @@
+
+name: Documentation request
+description: Ask for documentation to be added, changed, or removed
+title: "Docs: "
+labels: ["type/docs"]
+body:
+- type: textarea
+  id: what
+  attributes:
+    label: Is your documentation request related to a feature? If so, which one?
+    placeholder: A clear and concise description of the feature that you were trying to use, and what you were trying to achieve.
+  validations:
+    required: true
+
+- type: textarea
+  id: solution
+  attributes:
+    label: What is the solution that you would like or the expected outcome?
+    placeholder: A clear and concise description of the documentation that you want to add, change, or remove.
+  validations:
+    required: true
+
+- type: textarea
+  id: expectations
+  attributes:
+    label: What did you think would happen?
+    placeholder: A clear and concise description of what you expected to happen.
+  validations:
+    required: true
+
+- type: textarea
+  id: environment
+  attributes:
+    label: What was your environment?
+    placeholder: Infrastructure (e.g., Kubernetes, bare-metal, laptop), deployment tool (e.g., helm, jsonnet)
+  validations:
+    required: true
+
+- type: textarea
+  id: context
+  attributes:
+    label: Any additional context to share?
+    placeholder: Add any other context or screenshots about the feature request here.
+  validations:
+    required: false

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1 @@
+blank_issues_enabled: true