ubuntu-emulator create should include --developer-mode option

[Richard Huddie]

In order to enable automated testing of ubuntu emulator images we need a way to have developer mode enabled by default on new images. Currently it is only possible to do this by manually going to system settings and turning it on through the UI.

A --developer-mode option on the command line would be ideal, which would allow emulator images to be created with developer mode enabled by default. E.g.

ubuntu-emulator create my-emulator --arch=i386 --channel=ubuntu-touch/devel-proposed --developer-mode=True

[Vincent Ladeuil (vila)]

While the emulator is created, the log mentions:

[ 4.295252] init: cannot find '/sbin/adbd', disabling 'adbd'

But once the emulator is started and the developer mode turned on through the UI, adbd can be found under /usr/bin

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.