Added a new DTO to contain standalone posting rule information
Removed final modifier from delete method
Added a method to create a standalone enrolment gratuity posting rule
Created a delete method to not delete the Posting Rule if a Posting Rule for Standalone enrolments already exists
Implemented the feature to create posting rules for standalone enrolments in admin interface. Closes #376
Removed variable from method deleteDEAPostingRule and removed the type check in createDEAStandaloneGratuityPR
Removed useless comment
Added an error message when degree curricular plan service agreement template is null
Fixed class name
Merge pull request #394 from samfcmc/bug/403217

Closes #375
- added a new feature to manage the standalone posting rules in the 3rd cycle, with some validations avoiding future errors