Revised restrictions

[aoles]

Some spring cleaning of route filtering options across all profiles in the preparation for CALT release:

• for each profile, remove from avoid_features the following (if present):pavedroads, unpavedroads, tunnels, tracks and hills
• remove maximum_speed option
• for cycling and walking profiles, remove difficulty settings such as fitness_level, avoid hills, and maximum steepness

For details see https://github.com/GIScience/openrouteservice/projects/15.