Add support for Maps

[ElCapor]

It would be very cool to have an alternative to std::map in this library thanks !

[Sunrisepeak]

It would be very cool to have an alternative to std::map in this library thanks !

map is a adapter in dstruct, now have a implement by avl tree to support map's basics function.

map-adapter

https://github.com/Sunrisepeak/DStruct/blob/31522d6e0edd536fba3f0110c0eb27101feab91e/core/ds/Map.hpp#L50

examples

https://github.com/Sunrisepeak/DStruct/blob/31522d6e0edd536fba3f0110c0eb27101feab91e/examples/map.cpp#L19-L50

but it is very basic implementation. later, will add more underlying implementations can be chosen.(rb-tree....

[ElCapor]

Thank you very much sir !
I will use this and keep looking forward this project.