FEATURE: Improved user search in Dataset > Share menu

[brassy-endomorph]

Is your feature request related to a problem? Please describe.

1. Go to a dataset
2. Click Share
3. Start typing a user's name
4. No search results show up for a known user that 100% definitely exists in Keycloak (and eventually can be goaded into appearing in the UI)

This is incredibly frustrating because users may have multiple names, and I might know them as one name that is slightly varied from their name in Keycloak.

Describe the solution you'd like

1. Start showing users on the first key stroke. As a A should immediately return a user named Adam
2. Add fuzzy searching so that Jill will return Jil (one L)