Add `SET|SEQUENCE OF ANY` encoding support

For example:

  AttributeTypeAndValues ::= SEQUENCE {
    type OBJECT IDENTIFIER,
    values SET OF ANY DEFINED BY type
  }

This patch adds support of the above ASN.1 syntax to BER/DER/CER
codecs.

It appears that to implement this feature properly, `SetOf`/`SequenceOf`
pyasn1 types need to have `.componentType` wrapped into something
similar to `NamedType` that `Set`/`Sequence` have. That additional
layer would then carry the open type meta information. Without it,
`Sequence`/`Set` codec needs to signal `SetOf`/`SequenceOf` codec
of the open type being processed, which is a slight hack.

A other inconvenience is that when `SetOf`/`SequenceOf` deal with
an open type component, they should not verify types on component
assignment. Without open type property in `SetOf`/`SequenceOf`,
the code checks for `Any` component type which is another hack.

The above shortcomings should be addressed in the follow up patch.