DataPackageManager: Improve error message when an evaluation or upload conflicts with a reservation

[servilla]

If a vetted user attempts to evaluate or upload a data package with a package identifier that had been previously reserved, the error message states that the package identifier had been reserved by user labeled by their EDI profile identifier. The EDI profile identifier is obtuse and cannot easily be decoded:

icarus.3 is currently reserved by user EDI-d7a2ab54c046753874d21e8787348ee47a0ae41e. You should be logged in as user EDI-d7a2ab54c046753874d21e8787348ee47a0ae41e to evaluate or upload this data package. Alternatively, you could change the packageId of this data package to a value that does not conflict with the reserved identifier icarus.3

For privacy, the error message should not reveal any information about the user who reserved the package identifier, but it should provide the user who is attempting to evaluate or upload the data package with the next available identifier that can safely be used:

The scope and identifier "edi.16" is currently reserved by another user. Please select a different identifier value for the scope "edi" if you wish to evaluate or upload this data package. The next available identifier at this time for scope "edi" is "17".