Scheduler: Public Sessions Page Enhance it and fix date bug

[mariobehling]

The public session page needs to be enhanced and fixed as follows:

• the top of the page shows "today" as an option for the date, instead it should show the days of the event as an option
• for the display of the sessions, please use the full width of the middle content area
• use the track colors similar to the website generator, compare here https://sched.eventyay.com/FOSSASIASummit/rooms.html
• In the top right of the middle content area, please add an option to sort the sessions by a) Title (alphabetically), b) Speaker (alphabetically), c) Time/Date

Compare: https://eventyay.com/e/16fa59c7/sessions/all

[iamareebjamal]

Sorting by speaker won't be possible as mentioned in another issue as it is not a session property but a relationship and that too many to many. So, just adding ordering by title and time for now

[iamareebjamal]

Track color will be implemented after merging of #4836