Prepare release 3.9

[JohnRDOrazio]

• update PHP dependencies (swaggest/json-schema, phpunit/phpunit)
• add swagger validation badge to README
• remove deprecated LitLocale enums
• better locale handling (implement Locale::getPrimaryLanguage, simplify locale validity check, fix Locale class letter case )
• fix: wrong liturgical color for feast of Our Lord Jesus Christ King of the Universe
• add liturgicalSeason to Festivity output, and DateTime and Timestamp to the Metadata output
• remove unneeded request headers from Metadata output
• avoid defining year cycle for holy week and octave easter
• make sure sat mem BVM only Ordinary Time
• add isVigilFor key to vigil Masses
• implement CalendarType with types LITURGICAL and CIVIL
• output Liturgical Calendar as default (from first Sunday of Advent until Saturday of the 34th Week of Ordinary Time)
• track timing of calculations or read operations for pre-calculated / cached calendars, and add headers to Response: add X-LitCal-ExecutionTime header, add X-LitCal-Startime and -Endtime headers, add X-LitCal-Generated header
• fix rank Dedication Lateran Basilica
• allow national calendars to adhere to Feast of Jesus Christ Eternal Hight Priest fix issue https://github.com/Liturgical-Calendar/LiturgicalCalendarAPI/issues/96 enable Feast Eternal High Priest, update EternalHighPriest setting based on national calendar
• update schemas to account for new settings and new properties in response output