Add filename check to verify correct document uploads

[seanprivett]

https://trello.com/c/txwf1uO2

95% of uploaded files follow a specific format:

AAAACLIENTSURNAMEAAAA AAAFORMNAMEAAAAA 001.tif

We can check the client surname and the form name and provide visual feedback to the user that the file looks correct.

This would solve the following problems:
Sets of files uploaded for the wrong client
Incorrect document types uploaded: eg COP1A uploaded against the order

[acsauk-mojd]

@seanprivett - looks like that trello link is no longer active (or I'm not added to the board it links to) so I haven't been able to look at the designs. Shouldn't be too much to update once I see them as I've stuck with the GDS error div that already existed. I'll add some images/videos of it working once designs are accessible.

[seanprivett]

In some cases they will upload placeholder documents which are:

COP1A.docx
COP3.docx
COP4.docx

These won't have a client surname in the filename as they are generic documents.

System will prevent serving unless the checks pass.

Test double barrelled surnames, those with apostrophes. We should give some leeway here