feat: add support for annotations in application resource

[bonilla-cesar]

Description of your changes

This pull request adds support for annotations in the application resource. The motivation is to be able to include notifications for the lifecycle of the application and since they are configured through annotations I decided to make a contribution.-

Changes

• Implemented annotation support in the application resource.
• Added example how to use
• Testing updated

I have:

• [X] Read and followed Crossplane's contribution process.
• [X] Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

• Locally using kind

The reconciliation logs are oky

Annotations work as expected