Exclude self-intersecting (P-shaped) cycleways from "Unconnected cycleway" check

[Famlam]

Exclude cycleways that return to itself (in a P-shaped way). This fixes an incorrect warning about unconnected cycleways at the self-intersection point.

Technically enabled for all highways, but I guess the number of ways with level < 3 that self-intersect is negligible.

By using this instead of ST_IsSimple we make sure we still find cycleways that aren't connected on the "other end" too

Examples: It excludes: https://www.openstreetmap.org/node/2664365547 https://www.openstreetmap.org/node/11145455749 https://www.openstreetmap.org/way/1177282697 https://www.openstreetmap.org/way/1103314448 https://www.openstreetmap.org/way/768700323 https://www.openstreetmap.org/way/929852565

But keeps one of the endpoints in: https://www.openstreetmap.org/way/1207065702 https://www.openstreetmap.org/way/1138709520 https://www.openstreetmap.org/way/1207065702