Parser module

[amkozlov]

Create a new module parser, which will initially include following parsers:

• Model string: https://github.com/amkozlov/raxml-ng/blob/dev/src/Model.cpp
• RAxML-style partition file: https://github.com/amkozlov/raxml-ng/blob/dev/src/io/part_info.cpp

We agreed that this module will be written in C++, but we can also provide C interface if desired.