Source File Upload Tests

Add Uploaded source files testing. Handles success and error case.
Exception located in error cases, these tests are expect fail.
Added a 'Critical Error' check to BasePage and some hard defaults
for the document storage dir.
Added an action to delete the stored files on database reset.
Slight modification of ids in Source Documents pages.
Add too-large upload file test

Test for files that are too large to upload.
Fix up code review issues in Source Upload testing

Mostly blank lines and readbility.
Update UploadTest on review comments

Don't use globals for elements that may not exist.
Clear cached data between functions.
Wrong licence year.
Also added a test step for verifying the file is saved to the intended
location.
Use a generator instead of static files for testing

Rather than dumping a bunch of files in a dir, just use a generator
to create temp files.
Add a few more Upload tests to make use of this.
Completely clear and rebuild the h2 database on reset

The sql backup procedure for the first run scenario writes the
sequence lines without the "if not exists" clause, so subsequent
runs can fail - especially after the user has executed some
tests manually.
Drop all items from the database and either restore a base from
the backup or a complete database with test data.