Add is_fasse project attribute and fasse group tagging

[claire-peters]

Summary

• Adds is_fasse as a Yes/No ProjectAttributeType in add_default_project_choices
• Adds an is_fasse property to the Project model: returns True if the attribute value is 'True', False if the value is 'False' or the attribute is absent
• Adds CF_LDAP_FASSE_GROUP env var to ldap_fasrc.py config (opt-in, defaults to None)
• In collect_update_project_status_membership, resolves which project AD groups are MemberOf the configured fasse group and sets/unsets is_fasse on each project accordingly; no-ops if CF_LDAP_FASSE_GROUP is unset or the is_fasse PAT does not exist in the DB

Test plan

• Run manage.py add_default_project_choices and confirm is_fasse PAT is created
• Set CF_LDAP_FASSE_GROUP to the fasse AD group SAMAccountName and run collect_update_project_status_membership — confirm fasse projects get is_fasse=True and non-fasse projects get is_fasse=False
• Confirm project.is_fasse returns True/False correctly for both cases
• Confirm no errors or attribute writes occur when CF_LDAP_FASSE_GROUP is unset