Allow MP submission without PA sponsor

Currently, measure must have a PA sponsor in order to be considered for the deemed measures library. This is an obstacle for new measures.

1. Add a "Cal TF" option for the PA Lead field to allow Cal TF to develop and submit measures without a PA sponsor.

2. An alternative is to make “PA Lead” field optional (i.e., new measure without PA lead).

To ensure high quality standards are maintained, prevent measure developers from changing the status to "Submitted to CPUC" without going through "Cal TF Staff Review" and "Cal TF Affirmation" if measure does not have a PA Lead designation.