[ADC 1.0.2] Explicit note about Base32

Since a lot of people have had trouble with Base32 and (lack of) padding, I thought it would be good to add the following to the “general” section in the base document;

Base32 encoding is specified in RFC 4648. ADC excludes padding.

This should be fine to incorporate in the base document as it should not change any existing implementations.

This is in ADC 1.0.2, closing.