lang: add support for logging expected and actual values and pubkeys

[paul-schaaf]

closes #1586

closes #1464

Future PRs should add more require statements that abstract away the implementation details

macros added in this PR:

• require_eq macro that is meant to be used with non-pubkey values and results in the following output:

'Program log: AnchorError thrown in programs/errors/src/lib.rs:68. Error Code: ValueMismatch. Error Number: 6126. Error Message: ValueMismatch.',
'Program log: Left: 5241',
'Program log: Right: 124124124'

• require_keys_eq macro that is meant to be used with pubkey values and results in the following output:

'Program log: AnchorError thrown in programs/errors/src/lib.rs:73. Error Code: ValueMismatch. Error Number: 6126. Error Message: ValueMismatch.',
'Program log: Left:',
'Program log: HCGsxsDZEKWnaS5t7JBct6cyyLS6Jcx7Mmn4KjUQokZY',
'Program log: Right:',
'Program log: Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS'

These macros can be used like this require_eq(value1, value2) in which case they return an error defined by us or with a custom error require_eq(value1,value2,MyError:SomeError). The require macro has also been changed to work the same way

Log statement are intentionally Left and Right and not Expected and Actual because future require macros would not fit those descriptions (e.g. require_gt)

[armaniferrante]

merge conflicts