Migration - 2 of several (#5748)

* Remove obsolete files and update documentation links for Aspire testing

- Deleted favicon.png and AspireApp.sln files as part of cleanup.
- Removed write-your-first-test.md documentation and updated related links in toc.yml and hosting-startup-not-supported.md to point to the new Aspire testing overview.
- Updated links in the what's new documentation for Aspire 9.1 to reflect the new testing documentation structure.

* migrate: Does this count towards curation? :)

* Remove deprecated diagnostic documentation and update links to the Aspire diagnostics overview.

* Remove deprecated files and update documentation links for Azure integrations

- Deleted favicon.png and Dapr.sln files from the Dapr snippet.
- Removed SQLite Entity Framework integration documentation.
- Removed SQLite integration documentation.
- Updated links in local-auth-disabled-for-azure-resources.md for Azure Web PubSub.
- Corrected Azure Container Apps documentation link in aca-deployment-aspire-cli.md.
- Updated Azure Key Vault and managed identity links in azure-security-best-practices.md.
- Cleaned up caching integrations deployment documentation.
- Revised SQL Server integration deployment documentation.
- Updated test-deployed-app.md to fix link formatting.
- Adjusted dev-containers.md to remove unnecessary Docker reference.

* Update markdownlint configuration to include MD060 rule

Author: IEvangelist

.markdownlint-cli2.jsonc

@@ -66,7 +66,8 @@
             "style": "asterisk"
         },
         "MD051": false,
-        "DOCSMD010": false
+        "DOCSMD010": false,
+        "MD060": false
     },
     "ignores": [
         ".github/",