scripts: include kernel config when saving env

Signed-off-by: Claudio Mignanti <c.mignanti@gmail.com>
scripts: implement a restore function for env scripts

Signed-off-by: Claudio Mignanti <c.mignanti@gmail.com>
scripts: add push option to env script, this assume that a default remote is configurated

Signed-off-by: Claudio Mignanti <c.mignanti@gmail.com>