Solitaire parses accounts using two traits, FromAccounts and Peel. The
FromAccounts derive macro generates a function, `FromAccounts::from()`,
which calls `Peel::peel` to construct each field in the struct:
```
let example = Example {
foo: Peel::peel(next_account_iter(accs)?),
bar: Peel::peel(next_account_iter(accs)?),
baz: Peel::peel(next_account_iter(accs)?),
...,
}
```
The FromAccounts derivation also attempts to implement Peel for the
structure itself however, which means `Example` itself is embeddable as
a field in another accounts struct. This is only used in ClaimableVAA
which is a large source of confusion and the complexity is not worth
maintaining.
This commit removes the recursion by:
1) Removing the `impl Peel` derived by FromAccounts.
2) Removes the AccountInfo iterator from Context as it is no longer needed.
3) Adds the current parsed account to Context instead, safe thanks to (2)
4) Move message out of ClaimableVAA and pass in to verify everywhere instead.
5) Removes Peel/FromAccounts from ClaimableVAA.
82ea938317