chore: add bot config files and update issue templates (#7249)

* chore: add bot config files and update issue templates

* fix: exclude SIP

.github/ISSUE_TEMPLATE/sip.md

@@ -0,0 +1,31 @@
+---
+name: SIP
+about: Superset Improvement Proposal
+
+---
+
+## [SIP] Proposal for XXX
+
+### Motivation
+
+Description of the problem to be solved.
+
+### Proposed Change
+
+Describe how the feature will be implemented, or the problem will be solved. If possible, include mocks, screenshots, or screencasts (even if from different tools).
+
+### New or Changed Public Interfaces
+
+Describe any new additions to the model, views or `REST` endpoints. Describe any changes to existing visualizations, dashboards and React components. Describe changes that affect the Superset CLI and how Superset is deployed.
+
+### New dependencies
+
+Describe any `npm`/`PyPI` packages that are required. Are they actively maintained? What are their licenses?
+
+### Migration Plan and Compatibility
+
+Describe any database migrations that are necessary, or updates to stored URLs.
+
+### Rejected Alternatives
+
+Describe alternative approaches that were considered and rejected.