bitbake: toaster: startup script standalone mode

bitbake: toaster: startup script standalone mode

The toaster starter script was designed to be sourced in
a build environment and set up the build recording environment
to be used in an interactive mode.

For the standalone web server mode, we modify the toaster
script to be run directly from the checked-out sources,
without a build environment set up, and run the web server
alone. In the standalone mode, the build environemnts and
all build activities are controled through the web interface.

(Bitbake rev: c1db4ccf27bedcbab2f03e7539fdb11b042c4fb9)

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