More formats for encode/decode

One day, while tinkering with Iroh, I had a need to convert one identifier from Base32 to z-base-32. This sent me down a rabbit hole of all the binary-to-text encoding schemes. It turns out, there are quite a few out there.

This plugin provides the following bases:

• encode crockford: Crockford's Base32.

• decode/encode z32: z-base-32, a "human-oriented" base-32 encoding.

• decode/encode z85: ZeroMQ's Z85, a relaxed version (byte length doesn't have to be the multiple of 4).

• decode/encode base58: Base58, mostly used by cryptocurrencies.

As well as a number of miscellaneous encodings:

• decode/encode html: HTML entities escaping and unescaping.

• decode unicode: converts Unicode strings to plain ASCII using the deunicode library.