Remove Unnecessary Files

Why these changes are being made:
We are no longer using the old Fargate-specific and Lambda-specific
template files in any of the ECR modules.

How this addresses that need:
* Delete the old, no-longer-used template files

Side effects:
None.

Author: cabutlermit

README.md

@@ -132,7 +132,7 @@ This is a core infrastructure repository that defines infrastructure related to
 
 * Owner: See [CODEOWNERS](./.github/CODEOWNERS)
 * Team: See [CODEOWNERS](./.github/CODEOWNERS)
-* Last Maintenance: 2025-03
+* Last Maintenance: 2025-05
 
 ## TF markdown is automatically inserted at the bottom of this file, nothing should be written beyond this point