Add CMake option to build Valhalla with `-fno-rtti`

Some projects depending on Valhalla have a requirement to be built with `-fno-rtti` flag(for various reasons, mainly due to binary size). In general there are no any issues with Valhalla and `-fno-rtti`, but from time to time new changes are introduced in Valhalla which explicitly require RTTI: e.g. those ones which use `typeid` or `dynamic_cast`(https://github.com/valhalla/valhalla/pull/3191).
The idea is the following:
1. Introduce CMake option `DISABLE_RTTI`, which applies `-fno-rtti` if `ON`.
2. Configure CI job which would check if Valhalla can be built with `DISABLE_RTTI`.

cc @valhalla/core