Feature: Reminder for a pre-scheduled hike

[ItsAdityaKSingh]

After issue #5 is addressed we could further enhance it by allowing other users to pin a scheduled hike.
We could also give them notifications beforehand, on some set timers (say like 24 hours before -> 12 hours before -> 1 hour before), to be able to join the hike on time!

[ItsAdityaKSingh]

If this feature seems to be valid, I would like to work on it @nb9960

[nb9960]

Prescheduling the beacon is handled in #53 along with joining the pre-scheduled beacon, and notification is thrown when the beacon starts. Not sure if we still need this but still, it's open for discussion

[ItsAdityaKSingh]

In #53, a notification is displayed when the hike has started. One can be notified and reminded at a certain time interval earlier too if one forgets about it.