utilities: Add in a couple of useful utils

This adds push.sh, which will check for a deb with a basename in your
$PRODUCT_OUT/packages directory, copy it to the board, install it and
its dependencies.

It also adds shell.sh which functions the same as push.sh, except it
drops you to a shell.

Both of these are special since they elide host key verification.

Change-Id: I16a8df00977b5249a7c391f7e33fd81805f9cb62
2 files changed