L2SS-397: renamed primary datavalues to just 'values' instead of sst/xst/bst _values...

renamed primary datavalues to just 'values' instead of sst/xst/bst _values since the file is already named after the mode

Completely overhauled the hdf5_explorer.py and renamed it to statistics_reader.py. Can now parse multiple files and turns them in to a more readily usable format. Also has the capability to filter between a certain time range. Also provided several useful functions people could use. Such as getting a single huge numpy array of all statistics values or getting a specific statistic by timestamp.

This should hopefully provide a good base code for reading statistics files.

Closes L2SS-397