User is being added to an institution through his email field provided by ldap.
Tests are missing.

refs #1254
Principal name field added and views updated, tests are missing.

refs #1254
Ldap tests done.

refs #1254
User institution is now associated when logging in via LDAP.

refs #1254
LDAP info is not stored in the session, fix PR #5

Was getting the principal name from the session when signing in via LDAP,
but this information is not stored in the session (as it happens for Shib).
Moved most of the logic of setting an institution to a user to Mconf::LDAP
and remade the tests.

refs #1254
Merge PR #5 from 'gmiotto/branch-v2-1254-user-institution-ldap'

refs #1254