alphalem.conf: poky and botched-merge cleanup

Removed more poky-specific elements and removed some artifacts from the
last merge that got botched somehow.

Signed-off-by: Mike Lewis <mikelewis@alphalem.com>
alphalem-image-basic: used IMAGE_INSTALL_append

The Yocto Project ref manual recommends using "_append" over the append
operator "+=" to avoid unexpected behaviour. Seems like a good idea.

Signed-off-by: Mike Lewis <mikelewis@alphalem.com>