bash: split 'bash_config' into exports and options

Separate the bash exports and options into distinct files.
bash: Better comment exports; reduce history size

List exports alphabetically. Reduce history size limit to 10000. There
isn't much value in having it excessively large.
bash: keep history of previous shells in new shell
bash: recalculate lines & cols for window resize

After each command, check the window size to ensure that lines and
columns are correctly displayed at the new dimensions.
Add @alrra to acknowledgements