[Feature] Add up hours for those with AWS

[rrefoy]

For those with AWS or weekly billing projects (I think), your total hours are not calculated automatically. With 18F's push for a more granluar tocking experience, this would be helpful for me to make sure I'm not going over my hours but also tracking what I need to track. Happy to share more details if helpful.

[Sgtpluck]

Needs to be scoped down to be minimally implemented.

Will probably require some design and user research to make this easier for folks on AWS -- but probably won't align exactly with the way non-AWS users experience it because tock doesn't contain the OHRM concepts.

[melchoyce]

What engineering label would this fit under?

[MelissaBraxton]

We're removing this issue from our project board because it doesn't currently fit within our current initiatives or our strategic bets.