feat(sdk): add Extensions Manager

[pavelnikonorov]

Description (TBU)

Add SDK and CLI support for loading external extensions to provide additional functionality.

Add support for the optional use of additional TLS verification methods in the Transport struct.

Additional context

This issue is part of a meta issue #71 . Refer to it for context and additional information.

[pavelnikonorov]

Hey everyone, just a quick update regarding this issue :

• The current implementation of Transport support for extensible TLS-verifier methods was in a PoC stage and is now being transitioned to a conventional Rustls (Rust TLS library) custom verifier with a comprehensive trust states management.
• As part of this, the changes to transport.rs are being moved to a separate PR within the issue feat(transport): add support for extensible TLS verifiers #73 since they represent a separate concern and need a more structured approach.
• This will help keep this issue focused while ensuring that the verifier integration is properly handled.