Fix preference range formats

Change preference range format, eg

...	range_start	range_end
...	08:00:00	18:00:00
...	10:00:00	20:00:00

With type Time. Read more https://www.postgresql.org/docs/9.1/datatype-datetime.html

• Change BE model and apis to reflect this change
• Change FE api calls to reflect this change
• Change Routing to reflect this change