led-manager: add CLI11 option and config loading

To facilitate localized testing of JSON config loading, add an option
that allows the configuration to be directly passed, rather than try to
determine it from entity-manager config off dbus.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I80d7051bf312044c68f44bcdb9ac02364f9abac3
5 files changed