Function that maps location to location on hike

[mchac15]

Problem: The user location won't necessarily be exactly on the hike's line, but we want to display it on the hike nevertheless.

Thus we need a function that projects the actual user's position point onto the lines formed by the hike's waypoints, similar to the image shown below.

@MaelImhof and @davidholzwarth think this function is best put into LocationUtils, but if you have a different proposal please start a discussion about it.

[MaelImhof]

Adding this here for further documentation :

We discussed the function further on the Telegram group and decided it would be best to have it return three things :

• A projected location of the user onto the hike (even if the user is far away from the hike)
• The length of the hike the user has already done according to the projected location
• The distance between the actual and projected location. This will be used in the UI (not in the function) to determine using a threshold if the user is on the hike or not, and to display either the actual or projected location.