Update to Laravel 5.4 and Datatables 7.0

[murrant]

Please see our contributing docs

• [x] Have you created any necessary docs?
• [x] Have you created tests for Travis integration?
• [x] Have you used localisation in the WebUI?
• [x] Have you included the proper copyright?

You will need to composer update, php artisan cache:clear, php artisan view:clear You may need to rm storage/cache/*.php

Did not convert everything over, etc. Just basic get it up and running for the most part.

[mention-bot]

@murrant, thanks for your PR! By analyzing the history of the files in this pull request, we identified @laf and @f0o to be potential reviewers.

[murrant]

Testing updates pending...