[CORE-53] Refactor storage cost estimate to use Rawls

[trholdridge]

Rawls now supports getting workspace bucket location, so Orchestration doesn't have to directly request this information from Google, which was causing incorrect behavior around requester pays. This change modifies the storage cost estimate API so that it uses Rawls to get bucket location (for rate calculations). It also adds an optional userProject query parameter so that a reader may use the API to get a storage cost estimate on a requester pays workspace if they provide a project to bill.

For UI users, this will fix the error in getting estimated cost on requester pays workspaces for writers and owners. It won't look any different for readers, because the UI hides estimated cost from readers in the first place.

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I, the developer opening this PR, do solemnly pinky swear that:

• I've followed the instructions if I've made any changes to the API, especially if they're breaking changes
• I've updated the FISMA documentation if I've made any security-related changes, including auth, encryption, or auditing

In all cases:

• Get two thumbsworth of review and PO signoff if necessary
• Verify all tests go green
• Squash and merge. Make sure your branch deletes; GitHub should do this for you.
• Test this change deployed correctly and works on dev environment after deployment

[trholdridge]

I can just leave this + its implementations if that is better. It is not used anywhere else in orch which is why I deleted it.

[davidangb]

I didn't test it myself, but this looks great - thank you for all the cleanup!