feat: Handle tuple structs in IDL

[abhimanyusinghgaur]

This PR adds support for handling tuple structs in IDL. It names the tuple struct fields as f0, f1, f2, etc. The integer after f is the index of the value in the tuple.

Given a tuple struct in Rust like this:

#[account]
pub struct TupleStruct(u64, String, B, [i32; 5]);

The generated IDL looks like this:

    {
      "name": "TupleStruct",
      "type": {
        "kind": "struct",
        "fields": [
          {
            "name": "f0",
            "type": "u64"
          },
          {
            "name": "f1",
            "type": "string"
          },
          {
            "name": "f2",
            "type": {
              "defined": "B"
            }
          },
          {
            "name": "f3",
            "type": {
              "array": [
                "i32",
                5
              ]
            }
          }
        ]
      }
    }

Related to #232, #971.

[paul-schaaf]

is there anything in the way of merging this @armaniferrante ?

provided that we add changelog etc (do we have tests that test idl generation? I saw tests that check that rust types can be generated from strings but not that they result in the correct strings)?

[armaniferrante]

do we have tests that test idl generation?

Yes, but they are all implicit in e2e tests, which makes for significantly faster development. We should add a test here before merging.

[paul-schaaf]

@armaniferrante I suppose we can only test e2e if we add the ts code required to parse tuple structs in this PR as well then?

[darkmode-ff]

is this PR still active?

[abhimanyusinghgaur]

is this PR still active?

I won't be able to contribute further ATM. If anyone else is interested, they can take it up.

[acheroncrypto]

Superseded by #2824.