make Provisioning API aware of multiple mails

[blizzz]

This extends the provisioning API as following

getUser

endpoint: ocs/v2.php/cloud/users/2d42e983-a7a8-40b1-8e4a-b8afeb5244240b

Original response

<?xml version="1.0"?>
<ocs>
 <meta>…</meta>
 <data>
  …
  <email>person_11@example.org</email>
  <displayname>Isabel, Morgan (person_11)</displayname>
  …
 </data>
</ocs>

New, with no additional mail set

…
  <email>person_11@example.org</email>
  <additional_mail/>
  <displayname>Isabel, Morgan (person_11)</displayname>
…

New, with one or more additional mail set

…
  <email>person_11@example.org</email>
  <additional_mail>
   <element>test1@example.org</element>
   <element>test2@example.org</element>
   <element>test3@example.org</element>
  </additional_mail>
  <displayname>Isabel, Morgan (person_11)</displayname>
…

getEditableFields(ForUser)

endpoint: ocs/v2.php/cloud/user/fields/e8a7e882-5c5e-4f61-b6bb-bc5fd9b3cb4b

one entry added unconditionally

<?xml version="1.0"?>
<ocs>
 <meta>… </meta>
 <data>
  …
  <element>additional_mail</element>
  …
 </data>
</ocs>

editUser

endpoint: ocs/v2.php/cloud/users/2d42e983-a7a8-40b1-8e4a-b8afeb5244240b
method: PUT

• To add an additional email, just use 'additional_mail' as key.

• Deleting and setting scope is not possible with this endpoint as we need the value as reference.

editUserMultiValue

endpoint: ocs/v2.php/cloud/users/2d42e983-a7a8-40b1-8e4a-b8afeb5244240b/{collectionName}
method: PUT

• To remove a value, assign the email to the key parameter and leave the value empty. Future properties may implement renaming by using key as old value and value as new value.
• To set the scope, append the Scope suffix to the collectionName. key is the mail address, value the scope value.

---

contributes to #26866

[Pytal]

🎉🎉🎉

[skjnldsv]

/backport to stable22