feat: Add service-specific endpoints support to FSM config parser

Add support for parsing [services] sections with service-specific endpoint_url
configuration following AWS SDKs & Tools specification.

Changes:
- Extend Profile class with endpoint_url and servicesEndpointUrl map
- Add FSM states for [services] and [services serviceId] sections
- Add GetServiceEndpointUrl() and GetGlobalEndpointUrl() API methods
- Support case-insensitive service ID lookup
- Add comprehensive test coverage

Supports config format:
[profile default]
endpoint_url = https://global.example.com

[services s3]
endpoint_url = http://localhost:9000

 Add Profile computed getters using Aws::Crt::Optional for proper null handling:
  - GetServicesName() returns services definition name or empty Optional
  - GetEndpointUrl() returns global endpoint URL or empty Optional
- Add static Profile::GetServiceEndpointUrl() helper for endpoint resolution
  - Takes profile, services map, and serviceId as parameters
  - Maintains Profile as stateless data container
- Add AWSConfigFileProfileConfigLoader::GetServices() const accessor
Uses Aws::Crt::Optional instead of empty strings to properly represent
"no value" state. Static helper pattern keeps Profile ABI-stable while
enabling service endpoint resolution without coupling to loader internals.

added a test for multiple services definition

updated test to use .find before creatng the profile

update to use a service object instead of using getvalue

added 3 more tests verifying duplication urls, modify the services object with more encapsulation

Author: kai-ion