feat(api): Generate a blake2b hash of a given binary buffer.

[bkioshn]

Description

Generate a blake2b hash of a given binary buffer.
Related function include

• blake2b
• blake2bmac

Related Issue(s)

Closes #98

Description of Changes

Reference to blake2b can be found rfc and doc

Fix how blake2 is implemented, since when blake2 is keyed it changes to MAC (Message Authentication Code) mode.

• Divide blake2 into 2 functions
  • blake2b: blake2b and blake2bmac
  • blake2s: blake2s and blake2smac
• blake2 without key will only accept bytes of buf and optional outlen which is the output length of the hash (eg. if outlen = 32 the hash function is equal to blake2b-256)
• blake2mac accepts bytes of buf, optional outlen, key, optional salt, and optional personal
  If outlen is not specified, set to 64 which is blake2b-512
• Handle all possible errors
• Create rust unit test for blake2b and blake2bmac

Please confirm the following checks

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream module

[Mr-Leshiy]

Besides few comments LGTM

[stevenj]

Looks great.