Biscuit v3 support

[divarvel]

This is an umbrella issue for the support of the v3 spec in biscuit-go

Prep work

• provide convenience APIs for parsing whole datalog snippets (to implement parsing consistency tests in the samples suite) Refresh test suite #120
• update the samples and make sure they're part of CI Refresh test suite #120
• make specific samples easy to skip to follow implementation progression Refresh test suite #120
• merge or close outstanding PRs

v3 support

order has to be refined. Implementing 3rd party blocks will require a lot of changes in the datalog engine, so other tasks like check all might be better handled after.

• fix operator precedences Parser fixes #121
• add bitwise operators
• add !=
• audit expression evaluator to make sure methods are implemented on all supported data types
• make sure evaluation is aborted when an expression fails to compute
• 3rd party support
• check all support
• support parameter interpolation Parameters #122
• support querying an authorizer with scopes
• authorizer snapshots