2.1.0: Add better description and documentation handling (OSK-17) (#18)

Motivation
----
The current library doesn't have a decent README and the implementation
doesn't provide a good way to see all currently added cryptographic key
implementations to the dependency container

Modifications
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* Updated documentation
* Added new CryptographicKeyDescriptor to help integrations describe an
implementation via code
* Updated packages for security fixes

Result
----
library is better documented and has easier access to seeing
integrations

Fixes #17