Add some guidance around high accuracy

[cjpete]

It's so easy to enable it, but there is a non trivial cost if it's not needed. Particularly there is a significant delay on iOS to retrieve the initial location.

[ravirajn22]

I feel a wrapper library cannot add all nuances of how the underlying library works and its best practices, then the readme will become too big, unreadable in a glance and also becomes unmaintainable after a point. Better if we guide them to official docs for those kind of details, since the core library docs will always be up to date and will have best practice.