Feature/implement missing validations

See merge request !53

- mainly because there is no longer a name property in the core context v1.3

feat: add tcs for query subscriptions

See merge request !52

feat: implement test cases for delete subscription

See merge request !51

feat: implement test cases for retrieve subscription

See merge request !50

feat: implement test cases for update subscription

See merge request !46

feat: add missing tc for query context source registrations

See merge request !48

Feature/common behaviors

See merge request !49

feat: add checks on created updated and deleted entities

See merge request !42

feat: add checks on modifications made in the context broker for batch entities and csource registration subscription

fixed expectation file structure

See merge request !47

reviewed failing tests related to append/update entities: fragments not using contexts and wrong expectation format

See merge request !45

Feature/validation after create or update

See merge request !44

reviewed query entities tests

See merge request !41