Rename ByteSliceMode to ByteSliceLaterFormatMode, etc

[fxamacker]

This PR renamed ByteSliceMode to ByteSliceLaterFormatMode and also renamed related options.

For context:

// ByteSliceLaterFormatMode specifies which later format conversion hint (CBOR tag 21-23)
// to include (if any) when encoding Go byte slice to CBOR byte string. The encoder will
// always encode unmodified bytes from the byte slice and just wrap it within
// CBOR tag 21, 22, or 23 if specified.
// See "Expected Later Encoding for CBOR-to-JSON Converters" in RFC 8949 Section 3.4.5.2.

Also considered using ByteSliceLaterEncodingMode but the word "format" (i.e. encoding format) is probably less ambiguous for people unfamiliar with RFC 8949 Section 3.4.5.2.

[fxamacker]

@benluddy @x448 PTAL 🙏