refactor and test the use of the anyone keyword when sharing with JMAP

[florentos17]

tackling issue #5314

[florentos17]

• 1st commit: when implementing frontend support for subbaddressing, i had issues with a plain serverFail error without any description. it was actually a DifferentDomainException, the error handling can now pick it up ;
• 2nd & 3rd commits: some refactorings to be able to use anyone in a special entry key
• 4th commit: the integration test that show that a mailbox can now be shared with anyone

[florentos17]

the 5th commit comes with an open question, here is the spec:

`rights` of type `Rights`. The owner can see the full rights, but sharee MUST only see their rights if they do not have the administer right on the mailbox.
Sharee without administer right MUST NOT be able to see another SHAREE rights.

a sharee can see its own rights (as specified by the doc), but currently cannot see the rights granted to anyone. to me it would make sense to make this visible to the sharee. what do you think ?

[chibenwa]

[ISSUE-5314] integration test - a sharee should see the rights granted to 'anyone'

What for? I am rather against it as only 'p' right is visible.

Let's keep scope small. And not do that.