Remove unecessary tile coordinate unproject -> project step.
Unproject+project isn't always a noop and this was the issue leading to wrong cover calculation in high pitch values.
Fixes: https://github.com/mapbox/mapbox-gl-native/issues/15442
Patch partly fixes#15163 in a way that it doesn't allow loading tens of thousands of tiles and attempt to show area above horizon:
Limit pitch based on edge insets. It is not too bad - current limit of 60 degrees stays active until center of perspective is moved towards the bottom, to 84% of screen height. The plan is to split removal of 60 degrees limit to follow up patch.
Fix max Z calculation in getProjMatrix. TransformState::getProjMatrix calculation of farZ was complex with possibility to lead to negative z values. Replacing it with simpler, precise calculation:
furthestDistance = cameraToCenterDistance / (1 - tanFovAboveCenter * std::tan(getPitch()));
TransformState::getProjMatrix calculation of farZ was an aproximation. Replacing it with simpler, but precise calculation.
Related to: #15163
ported from -js: eb6c6596c6a7a61363d30356674e0002153b1d19
`altitude` was a terribly-named variable that was used to indirectly
control the fov. This should eliminate some confusion.
`altitude` was equivalent to `cameraToCenterDistance / height`
