The default value of plugins.allowRemoteAdmin is false, which is
a sensible default, but is annoying to have to manually enable for
every test site.
Make it less annoying by enabling it by default in developer mode.
Introduce a new init step that is run when developer mode is
enabled, i.e. when --dev is given and the site is initialized for
the first time.
It may seem like overkill to have a dedidated init step only to
set plugins.allowRemoteAdmin, but this will also allow us to set
any other developer mode specific settings in future.
Change-Id: Ia22b24570d696111d10006203c1bdacc4db31022
861123bde0