feat: add ServicesContext Extension

[shekohex]

This pull request introduces a new ServicesContext trait and its corresponding derive macro to the context-derive crate, along with updates to existing test files to incorporate this new trait. The most important changes include adding the ServicesContext module, implementing the derive macro, generating the context implementation, and updating the test cases to use the new trait.

New ServicesContext Trait and Derive Macro:

• macros/context-derive/src/lib.rs: Added the services module and implemented the derive_services_context function to generate the ServicesContext trait implementation. [1] [2]
• macros/context-derive/src/services.rs: Implemented the generate_context_impl function to generate the ServicesContext implementation for the given struct.

Test Updates:

• macros/context-derive/tests/ui/01_basic.rs: Updated to derive ServicesContext and added async block to test the new trait methods.
• macros/context-derive/tests/ui/02_unnamed_fields.rs: Updated to derive ServicesContext and added async block to test the new trait methods.
• macros/context-derive/tests/ui/03_generic_struct.rs: Updated to derive ServicesContext and added async block to test the new trait methods. [1] [2]

SDK Integration:

• sdk/src/ctx.rs: Added the ServicesContext trait definition and its methods.
• sdk/src/lib.rs: Exported necessary modules for ServicesContext.

Part of #265

[drewstone]

CC @Tjemmmic here we will need an integration with the Eigenlayer service manager contract to