Add support for dimensions to transactions overview

[alexdglover]

As a user, I want to be able to drill into a specific category and see all associated transactions, so that i can see what events contributed to that total spend by category (including incorrectly categorized transactions).

As a user, I want to be able to drill into a specific account and see all associated transactions, so that i can find a specific transaction I'm interested in.

As a user, I want to be able to filter transactions by different criteria, so that i can easily find specific transactions or review a subset of transactions as a single group.

Once support is built for this, update the accounts pages and spending by category page to support drill down into the transactions view.