[EuiTable] Add `EuiTableUtilityBar` component

[tkajtoch]

Summary

As part of the tables sweep initiative, we want to add selection persistence to <EuiInMemoryTable>. The new EuiTableUtilityBar component is needed to render the selection information and necessary buttons.

Acceptance criteria

• The new EuiTableUtilityBar component should be implemented following the design
• The component should provide generic, configurable space for the following:
  • Pagination information - required, always visible text (e.g., Showing 1-19 of many items)
  • Expandable Selected button - visible when items are selected
  • Expandable Bulk actions button - visible when items are selected
• Clicking on the Selected button should open a popover with the related actions:
  • Select all - optional
  • Clear selection - resets the selection state (and makes the Selected and Bulk actions buttons disappear)
• Clicking on the Bulk actions button should open a popover with configurable actions