feat: add turnkey signer to aa-signers

[moldy530]

• feat: add turnkey signer to aa-signers
• test: add tests for turnkey signer
• refactor: use turnkey stamper interface
• refactor: rename TurnkeyAuthMetadata
• docs: add turnkey aa-sign docs and update turnkey snippet
• refactor: use webauthn stamper in turnkey test and examples
• docs: add turnkey section in aa-signers. update turnkey smart account doc
• chore: accidentally deleted yarn.lock in 8fb9b74. run linter
• docs: turnkey smart account doc
• docs: include new turnkey/iframe-stamper as auth option
• refactor: use resolveSubOrganization for turnkey auth params

Pull Request Checklist

• Did you add new tests and confirm existing tests pass? (yarn test)
• Did you update relevant docs? (docs are found in the site folder, and guidelines for updating/adding docs can be found in the contribution guide)
• Do your commits follow the Conventional Commits standard?
• Does your PR title also follow the Conventional Commits standard?
• If you have a breaking change, is it correctly reflected in your commit message? (e.g. feat!: breaking change)
• Did you run lint (yarn lint:check) and fix any issues? (yarn lint:write)
• Did you follow the contribution guidelines?

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PR-Codex overview

This PR adds support for the TurnkeySigner in the signers package. The notable changes include:

• Exporting the TurnkeySigner and TurnkeyAuthParams from the turnkey/index.ts file.
• Adding the TurnkeySigner and TurnkeySubOrganization classes to the turnkey/signer.ts file.
• Adding the TurnkeyAuthParams, TurnkeySubOrganization, and TurnkeyUserMetadata interfaces to the turnkey/types.ts file.
• Adding the getAddress, signMessage, getAuthDetails, and signTypedData methods to the site/packages/aa-signers/turnkey/ directory.
• Adding the constructor method to the site/packages/aa-signers/turnkey/constructor.md file.
• Adding the getAddress, signMessage, getAuthDetails, and signTypedData methods to the site/packages/aa-signers/turnkey/ directory.

The following files were skipped due to too many changes: packages/signers/src/turnkey/signer.ts, site/packages/aa-signers/turnkey/introduction.md, packages/signers/src/turnkey/__tests__/signer.test.ts, site/smart-accounts/signers/guides/turnkey.md, site/packages/aa-signers/turnkey/authenticate.md, yarn.lock

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[avasisht23]

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