The codecs module mostly but not fully supports non str<->bytes codecs

Bug report

Bug description:

There's in the codecs module an option for charbuffertype which allows bytes<->bytes codecs, but if there were a type for the encoded value, it would allow cleaner implementation of str<->str codecs, or more...
Most codecs in CPython use decoded str and encoded bytes, there are also codecs that have decoded bytes and encoded bytes, like base64 (note that a base64 codec arguably could be one that considers decoded bytes and encoded str).

I had been more or less perverting the codecs module to implement things like COBS (fundamentally bytes<->bytes), bubblebabble (I did bytes<->bytes but it should encode to str), and recently ANSI escape filtering, as a str<->str codec that works by implementing a virtual terminal, with a screen buffer. To make it work I only had to do self.bytebuffer = "" in the StreamReader constructor, but since there's a charbuffertype, maybe we could use a bytesbuffertype, and open the flood gates to all kinds of creative abuse.

CPython versions tested on:

3.12

Operating systems tested on:

Linux

Comece pelo módulo codecs e inspecione o construtor de StreamReader, incluindo o comportamento existente de charbuffertype. Determine o modelo pretendido para os tipos de valores codificados e decodificados e, em seguida, defina o que um suporte mais amplo a codecs além de str/bytes deve abranger; o trabalho só estará concluído quando esse escopo e seu comportamento esperado estiverem estabelecidos e implementados.