Change start_date & end_date logic to individual component to match the api

[kggx]

A date_from, date_end, time_from & time_to parameter can be added to the Exploration-API Query.

• date_from: Start date in the query
• date_to: End date in the query
• time_from: Start time of an event
• time_to: End time of an event

How ever currently the module expects a point in time for either start_date or end_date and parses automatically date_from and time_from as well as date_to and time_to. This will result in a unexpected results

Proposal is to change the input into individual parameters and mark start_date & end_date as deprecated

Blocks #4

[kggx]

LGTM