Add DatasetDiscovery annotation

Description

Add DatasetDiscovery annotation :

 @Target(TYPE)
 @Retention(RUNTIME)
 @ConfigurationType("datasetDiscovery")
 public @interface DatasetDiscovery {
 String value() default "default";

Add a base class for DatasetDiscovery configuration to inherit from with boolean property to check if user wants the dataset to be returned.

Modify DatasetValidator so that it allow a Emitter class to have a Dataset OR a DatasetDiscovery attribute.

Acceptance Criteria

• Ability to create new @DatasetDiscovery kind of configuration
• Retrieve those kind of configuration thanks to a rest call to the component server
• Having validation that force @DatasetDiscovery having a nested @Datastore + normal validation (should be same validation that for @Dataset + inheritance of DatasetDiscoveryConfiguration that contain 1 mandatory option)
• Using @DatasetDiscovery in a mapper/input connector

DoR

The feature is "Ready" when all DoR check marks are 

Possible status of the checkmarks:

•  ready, complete
•  missing some information
•  not started to complete

Topic	Description	DoR
Description	Is the user-story properly defined?
Acceptance Criteria	Are they defined? Were they validated by PO, Dev and QA?
Jira information	Is the Jira information correct? (fix version, labels, security level)
Environment	Environment ready Support SSL Reachable for QA/Doc/automation(TTP, Junit)
License	Is license EE or SE clearly identified ?
Technical Analysis	Does the developer understand how it will be implemented? Do we have a solution? Approved/discussed with architecture (in-team, global or security, depending on the scope)?
Dependencies	Are all dependencies linked to JIRA (link "depends on")? Are they done? Including SRE/Devops/IT
Migrations	Is migration needed?
Doc	Is DOCT created and linked under the epic? Not DOCT but has to update TCK documentation to be visible in tck web site.
Communication channel	Is slack feat- created? With all the correct owner involved? (QA/Doc/PO/SM) : #eng-dataset-discovery
UX	Are there changes in the UI & were they added in the DOCT? For new forms, was it approved by UX? For new connectors, was a TUX ticket created for a new Icon?