add more flexible date and time format

[aymericingargiola]

Add more string options to format time and date :

start_time (string: HHMMSS): Stream start time, UTC timezone
year (string): Year extracted from stream start date, UTC timezone
month (string): Month extracted from stream start date, UTC timezone
day (string): Day extracted from stream start date, UTC timezone
hours (string): Hours extracted from stream start date, UTC timezone
minutes (string): Minutes extracted from stream start date, UTC timezone
seconds (string): Seconds extracted from stream start date, UTC timezone