Support acloud list command.

Enable the ability to list remote instances created by the user
and disply the info of instances including avd spec and status.

Bug: 118405737
Test: acloud list && acloud list -v && acloud delete
atest acloud_test

Change-Id: I8420f69c8f8c30046eeffe95c5b5d2d184ec4738
10 files changed