Fixing usage of whitelist in commit script

Description of bug

The commit script would cd into the directories that we wanted to add to a commit and list the files locally, which given the new rules would not pass the whitelist rules, since they would not have the [0-9]{3}xxx/[0-9]{6} prefix.

Changes introduced

• Commit script will not cd into the directories to be added to the commit, instead the contents in a given directory will be listed and passed to the checkWhiteList call with their full paths
• Changed the behaviour of the commit script to not add whole directories like Sherpa_i but instead list their contents and add the files in those directories according to the whitelist rules. Practically only GENERATOR/*.py files are allowed.
• Removed all directories from the whitelist

Tests

Checked that

• python files are recognised both in DSID directories and in DSID/Sherpa_i etc
• dat files are recognised successfully when they are directly in the DSID directory (DSID/sample.dat) and they are blocked when residing in DSID/GENERATOR/sample.dat (in the example below 950xxx/950031/Sherpa_i/sample.dat is skipped)
• GRID files added as links also seem to be recognised correctly

This should solve the problem experienced in !256 (merged)

Closes #78 (closed)