Add implementation issue template (#8176)

.github/ISSUE_TEMPLATE/implementation-ticket.yml

@@ -0,0 +1,39 @@
+name: 🛠️ Implementation
+description: This is an implementation ticket intended for use by the maintainers of dbt-core
+title: "[<project>] <title>"
+labels: ["user_docs"]
+body:
+  - type: markdown
+    attributes:
+      value: This is an implementation ticket intended for use by the maintainers of dbt-core
+  - type: checkboxes
+    attributes:
+      label: Housekeeping
+      description: >
+        A couple friendly reminders:
+          1. Remove the `user_docs` label if the scope of this work does not require changes to https://docs.getdbt.com/docs: no end-user interface (e.g. yml spec, CLI, error messages, etc) or functional changes
+          2. Link any blocking issues in the "Blocked on" field under the "Core devs & maintainers" project.
+      options:
+        - label: I am a maintainer of dbt-core
+          required: true
+  - type: textarea
+    attributes:
+      label: Short description
+      description: |
+        Describe the scope of the ticket, a high-level implementation approach and any tradeoffs to consider
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Acceptance critera
+      description: |
+        What is the definition of done for this ticket? Include any relevant edge cases and/or test cases
+    validations:
+      required: true
+  - type: textarea
+    attributes:
+      label: Context
+      description: |
+        Provide the "why", motivation, and alternative approaches considered -- linking to previous refinement issues, spikes, Notion docs as appropriate
+          validations:
+      required: false