New Sessions: Session capability clarification and Other Session adjustments

Sessions: when selecting other, we should be able: * add horses like we do volunteers or participants...use case: Ferrier visit is typically multiple horses * participants should not show up as a section in the session...if we have an event with participants, we would use 'Lesson' during the new session creation process Source: https://24trots.com/sessions/ses_RFyD1t90lnL8

Sessions: when selecting other, we should be able: * add horses like we do volunteers or participants...use case: Ferrier visit is typically multiple horses * participants should not show up as a section in the session...if we have an event with participants, we would use 'Lesson' during the new session creation process Source: https://24trots.com/sessions/ses_RFyD1t90lnL8