supervisor: new package

[thomas.petazzoni@free-electrons.com:
 Fixup indentation of Config.in file.
 Add 'depends on BR2_PACKAGE_PYTHON' so that the package does not
 appear when the Python interpreter is not enabled.
 Add license files information, but not the license tag: the package
 includes software under multiple licenses.]

Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>