Andrew Stoycos f3262e87bd Make map APIs return an option
switch map() and map_mut() from returning a
`Result` to an `Option` since it's just getting
a value from a Hashmap, and to stay in line with
the Programs API.

Remove `MapError::MapNotFound`

Signed-off-by: Andrew Stoycos <astoycos@redhat.com>
..
tests Make map APIs return an option
main.rs preserve existing behavior and avoid changes to gh workflows/xtask