opkg: Update to version 0.2.0

Signed-off-by: Paul Barker <paul@paulbarker.me.uk>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
opkg: Add PACKAGECONFIG options

Instead of hardcoding EXTRA_OECONF to disable things, we add PACKAGECONFIG
options for gpg, curl, ssl-curl, openssl, sha256 and pathfinder. By default all
these options are disabled.

Signed-off-by: Paul Barker <paul@paulbarker.me.uk>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
opkg: Don't use update-alternatives

The symlink from 'opkg' to 'opkg-cl' doesn't need to be created with
update-alternatives as there isn't any alternative. Instead it can be created by
hand in do_install_append.

Signed-off-by: Paul Barker <paul@paulbarker.me.uk>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>