refactor(lib): Allow fitting whole population at once

The fitness function gets fit_population function. The default
implementation is going over fit() one by one, but it can be
reimplemented by specific types.

chore: move env to codes/eoa_lib

refactor: Add dimension generic to BinaryString

chore: remove unused imports

refactor: properly handle errors in local_search

refactor: Use OVector instead of SVector in library

feat: add real fitness functions

Add linear, step, rastrigin, griewank and schwefel fitness functions
along with the tests for them.

Try using static vector where appropriate, but use OVector for those
where filling with zeros won't work. This is mostly a constrain for
the tests... rather than a real constrain. In the end the dimensions
will be given for each problem.

chore: split types and functions to separate module files