Build/Test Tools: Introduce a command for restarting the local Docker environment.

This change introduces the `env:restart` command for easier restarting of the local Docker environment.

Props desrosj, ianbelanger.
Fixes #50039.

Built from https://develop.svn.wordpress.org/trunk@47730


git-svn-id: https://core.svn.wordpress.org/trunk@47507 1a063a9b-81f0-0310-95a4-ce76da25c4cd