Implement auto-complete for hero select

[stocky37]

Required to properly change over to new api implementation (#93)

To Do

• Fix bug with null value when clearing
• Fix default value on initial load
• Fix bug where it scrolls to page bottom when selecting items from menu with arrow keys

[stocky37]

Scrolling bug is hidden when removing position="static" is removed from the toolbar. It appears the page still scrolls but this has less noticeable effect since the toolbar follows the page down.

[stocky37]

Also want a hierarchy of sorts for the way I have the autocomplete implemented, where I have a re-usable basic autocomplete component that uses a standard-ish api to MUI inputs.

[stocky37]

For the default value::

defaultSelectedItem={{ label: '4-LOM', value: 0 }}

This will change if/when mui-downshift upgrades to downshift v3