Clean up texts and some whitespace. Some strings into t().

I basically read all the English texts and edited them to my understanding. Please check the accuracy of my changes. I tried to gravitate towards language where there is a client site and a server site. The client site is where the patches are uploaded and the server site is the one that runs the tests.

One thing I wasn't 100% sure about is this:
'#description' => t('A password of your choice. Does not correspond to any Drupal user account. You will need to enter this password on the server site as well.'),
Is that description accurate?