Binding JavaSource is not incremental.

### Android application type

.NET Android (net7.0-android, etc.)

### Affected platform version

Any .net 7+

### Description

Our binding build process has never really been incremental. If files change the user currently needs to rebuild the binding to make sure that no old code is included. Since we can now include bindings directly into the main app we should do the work to fix this issue.

- [ ] Firstly we need to get `generator` to output a list of files which it generated.
- [ ] Use the file list from above to remove files which are no longer needed

### Steps to Reproduce

1. Create a new .net android app
2. Add an AndroidJavaSource item which some java code
3. Built it.

### Did you find any workaround?

none

### Relevant log output

_No response_