Rename apply command to sync

[Jonesy]

Consensus is that sync would be a better verb to describe what the command is doing behind the scenes than apply.

[Jonesy]

Will tackle this once all the latest apply changes have been merged into main.

[ikethecoder]

Will apply this in the future - clients have started to use the new CLI with the apply command so don't want to impact them with a change of command name; closing for now.