bitbake: retrieve the entire ui module in launcher

Slight change in bitbake as to retrieve the entire UI module
for further processing instead of just the main function.

Based on a patch by Bogdan Marinescu <bogdan.a.marinescu@intel.com>

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
bitbake: move extra cache collection out of cooker

The collection of the extra caching data should not
be performed by the cooker, but supplied to it.
This patch will also streamline the code for launching servers
without a UI attached.

Based on a patch by Bogdan Marinescu <bogdan.a.marinescu@intel.com>

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
bitbake: move start server code in a separate function

This is a code sanitization targeted at making further
server-related changes easier (launch a server
separately or creating a mockup-server) to do.

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>