Reduce amount of heap allocated types making it more secure

[beef331]

This PR removes ref object as it's not needed and it just increases the chance of a heap attack. It also disables copies on the objects to prevent accidentally keeping the secret in memory at multiple places. Finally it bumps nimble versions and pins base32. This is a breaking change but hopefully for the better 😅

[ba0f3]

Thank you!

[beef331]

As mentioned in the comments we could look at using stack_strings to store the secret in a stack allocated matter, the major issue there is that it means we're forced to a fixed size. Meaning secrets have to be a specific size or smaller. My thought was to have a otp.secretSize that users could use to define their secret length, which would be defaulted to 32. If this is something you're interested in I'll make a PR.

[ba0f3]

That's greet, a PR is welcome. Thank you!

[ThomasTJdev]

This is a breaking change but hopefully for the better 😅

@beef331 - would it be possible to add the breaking changes in a changelog? Or in the release tag?