GenStat BS3 / cleanup

A few more pages cleaned up - notable the depreciated `barcode_vs_expected.html` page, which now produces plots which can be read. Also several template pages which weren't being used for anything have been deleted.

Also a big cleanup in the `flowcell_samples.html` template - no manger change in functionality here, lots of reformatting the code so that I could read what was actually happening in the HTML (messy to review, sorry). Also changing some markup to use BS3 classes. **Change in functionality:** instead of showing "not found in DB" I've just hidden missing fields. Makes the page far smaller and easier to use I think. @Galithil - I'm pretty sure this will be going against what someone has asked you to do, sorry! Feel free to argue the point, or get me to pass it by any other interested people.

Phil
That's where we disagree.
For me, it takes a string, assuming it's a date with 6 chars, and splits in accordingly. It the data source is different in any way of what is assumed ... well it breaks. For instance, if the date becomes 20141022 (which might happen, as we have no control over our fields), what would this display ?
2020-14-1022.