Add status update batch action to invoices table

[sandeepsajan0]

Description

Fixes part of #3537

Test Steps

• Invoices table should be accessible to staff and finance
• Staff and Finance both should have the option to select the invoices and update their statuses(depending on their statuses)
• Check the statuses order like finance shouldn't be able to paid an invoice that is not Approved by finance yet.
• Play around and provide your feedback.

[wes-otf]

In testing when there were two invoices that had the status Paid, selecting both of these and attempting updating the status to Payment failed results in a 500 with:

sequence item 0: expected str instance, NoneType found

At activity_feed.py. More info in sentry but it still seems to update the status. Seemed also specific to these statuses as others would update w/o issue. This was done as the finance role.

[sandeepsajan0]

@frjo Its latest version is ready to put on test.
@wes-otf There were issues with older invoices because we added invoice_number recently to the invoice model and as nobody was using the project/invoices so we didn't handle it for the older ones and let it None.

Although this was working fine for invoices with invoice_number so it wouldn't make any issue on prod still I have added a check to resolve this issue for older invoices as well.
It seems working fine now, you may try it again after the latest code deployment.

[wes-otf]

For some reason now whenever I go to /apply/projects/invoices/ on test I get a 500 page cause by the error:

Missing staticfiles manifest entry for 'js/apply/jquery.fancybox.min.js'

Which is weird, was there an issue with collectstatic on the deploy or something?

[frjo]

@wes-otf I missed doing a rebase for this PR, we have recently flatten the dir structure in another PR.

Should be fixed now.