Add "To Base62" and "From Base62" operations

[tcode2k16]

Hi,
I added the "To Base62" and "From Base62" operations. These two operations should function the same as base62.io.

[CLAassistant]

All committers have signed the CLA.

[n1474335]

Thanks very much for the contribution, this is great.

I tidied up a number of things:

• Make sure you include a descriptive description.
• You were converting to and from the byteArray format unnecessarily. By simply defining your input or output type as "byteArray", this will all be done behind the scenes for you. If you do it yourself, you may add extraneous conversion steps in more complex recipes.
• We generally like to expose configuration options to the user where relevant. The alphabet in this case seems like a potentially useful thing for the user to be able to change, so I added an argument for it.

Thanks again, this has now been merged into version 8.14.0.