Unify snapping behaviour across services

[aoles]

Is there an existing issue for this?

• I have searched the existing issues

Problem description

Snapping of coordinates to the road networks varies wildly across endpoints and services as it is controlled by parameters named differently and with varying default values:

• directions: profile-specific config setting maximum_snapping_radius = 400 which can be overridden by query parameter radiuses
• isochrones: no limit, the maximum available radius of location index is being used (same as radiuses = -1 for directions)
• matrix: service-specific, profile-independent config parameter maximum_search_radius = 2000, no query parameter
• snapping: query-time parameter radius = 350

Proposed solution

Common defaults and handling of snapping across different endpoints based on the current one for the directions endpoint:

• profile-specific config parameter for the default value of snapping distance
• which can be overridden at query time

[aoles]

See also #538.