Improve StreamSeekable's constructor arguments

[phrocker]

StreamSeekable constructors are confusing [1]. Since references are used, it implies that we're doing a copy constructor of objects. It would make more sense to either not pass by reference when using std::move(...) as this implies an r-value reference. Prefer to copy or change the constructor to NOT use references for moves.

Also would be a good opportunity to move away from header only to speed up builds.

[1] https://github.com/phrocker/sharkbite/blob/master/include/data/streaming/accumulo/StreamSeekable.h