joinToFamily
Join to family by inviteHash with memberName.
See also
https://be-saas.cloudike.com/backend_docs/rest/api/2/core_pkg/family_app/Members/OpenFamilyMembers.html#post
Throws
SessionIsNotInitializedException
Session is not active.
Bad invite hash.
Unauthorized access.
UserAlreadyMemberOfFamilyException
When the user is already a member of a family.
UserMemberOfOtherFamilyException
When the user is a member of an other family.
Other problems.