prepare_ns() will need to be called from alternate views, and namespaces
will need to be created via different interfaces. So refactor and
allow specifying the view ns.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Signed-off-by: NJohn Johansen <john.johansen@canonical.com>

Policy namespaces will be diverging from profile management and
expanding so put it in its own file.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>