[disjoint] add alternative (more robust) implementation of segment-box disjointness test; the alternative implementation does not use any divisions
[distance] Add variant support

Add variant dispatch layer to the distance algorithm
[distance] Add variant tests

No finished yet
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint
[distance] First step to fix tests
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint
Merge from upstream
[distance] Merge from upstream
[distance] Fix some typo and add more tests
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint
[distance] Use transform_variant

Remove dependency to is_implemented. Update transform_variant to support
MPL sequence input.
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint
[doc] Extended doc for WKT
[crosses] Add variant support
[assign] Add variant support
[doc][wkt] update of conformance sections
[buffer] fix for update get_turns
[buffer] fix for changed name geometry_multi_within_coe to point_in_geometry