Parse and encode coordinates in omaps.app links

Historically, Organic Maps supports encoded location links: https://omaps.app/0yxdjqU7NK/Amathus

10 years ago it was important to save a few bytes when using SMS for sharing. Now it's better to share clear coordinates like this: https://omaps.app/34.71399,33.14058/Amathus

Coordinates are already supported by omaps.app url parser, but they are not supported yet on iOS and Android. The parser code should be easy to fix in the C++ code, plus add a few unit tests.

After implementing the parser and releasing app updates, the next step is to change/update the link encoder to produce readable links with coordinates instead of encoded sequence.