Fixes#1792.
This PR adds filter functionality to the web UI via an optional Material-UI <Toolbar> on the top of the table which contains the table's title and a filter icon. The toolbar only shows if the enableFilter={true} prop is passed down from the parent component. The PR modifies the MetricsTable test and adds tests for BaseTable and TopRoutesTable.
Note: The previous Ant-based UI allowed certain tables to be filtered by individual table column; this capacity is not part of this PR but can be added later if useful.