The gn tool recipe is not usable on dunfell due to python2
dependencies, and the current AGL solution for web applications
does not require building Chromium with the SDK, so remove the
recipe and the packages explicitly added for Chromium to cut down
on the SDK size and build time.
Bug-AGL: SPEC-3302
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I7e99f2c7711d2fad9d7608a734a2d96f2cb52e48