Person endpoints: filterBy in program

These are about filtering on people from one program based on their username/displayName/number.

Endpoint (Method): filterInProgramByUsername

Params	Type	Comment
Input	String	username
	Long	programId
Output	List<PersonViewDTO>	people

What does this method do?

1. Maybe it's possible to reuse the filterByUsername method (#46 (closed)) and then only get those in specified program?

Endpoint (Method): filterInProgramByDisplayName

Params	Type	Comment
Input	String	displayName
	Long	programId
Output	List<PersonViewDTO>	people

What does this method do?

1. Maybe it's possible to reuse the filterByDisplayName method (#46 (closed)) and then only get those in specified program?

Endpoint (Method): filterInProgramByNumber

Params	Type	Comment
Input	Integer	number
	Long	programId
Output	List<PersonViewDTO>	people

What does this method do?

1. Maybe it's possible to reuse the filterByNumber method (#46 (closed)) and then only get those in specified program?