NOISSUE - Refactor http and grpc clients for reusability with Cube (#521)

* Implement gRPC server with TLS and mTLS support

- Added gRPC server implementation in pkg/server/grpc.
- Introduced server configuration options for TLS and mTLS.
- Implemented health check service for gRPC.
- Created tests for server initialization, startup, and shutdown scenarios.
- Added mock server for testing purposes.
- Implemented graceful shutdown handling for the server.
- Included documentation for the server package.

Signed-off-by: SammyOina <sammyoina@gmail.com>

* Add TLS and ATLS support to gRPC and HTTP clients; refactor security handling

Signed-off-by: SammyOina <sammyoina@gmail.com>

* Refactor server configuration structure to use Config instead of BaseConfig

Signed-off-by: SammyOina <sammyoina@gmail.com>

* Fix comments for consistency and clarity in TLS-related code

Signed-off-by: SammyOina <sammyoina@gmail.com>

* Add comprehensive tests for TLS and ATLS configurations in clients package

Signed-off-by: SammyOina <sammyoina@gmail.com>

* Refactor file permission constants in client tests to use octal notation

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* Add tests for HTTP server's TLS configuration and lifecycle management

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* Add comprehensive tests for TLS certificate handling and configuration

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* Add comprehensive tests for HTTP client configuration and transport

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* Refactor AttestationReportSize constant declaration for clarity

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* Refactor client configuration structure and update gRPC client implementations

- Consolidated client configuration types into a unified structure with BaseConfig.
- Introduced AttestedClientConfig and StandardClientConfig for specific use cases.
- Updated gRPC client creation functions to utilize new configuration types.
- Refactored tests to align with the new configuration structure.
- Removed redundant ClientConfiguration interface and related methods.
- Simplified TLS configuration loading logic for both standard and attested clients.

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* Refactor client configuration structure and TLS handling

- Introduced StandardClientConfig to replace BaseConfig, simplifying client configuration.
- Updated AttestedClientConfig to embed StandardClientConfig instead of BaseConfig.
- Modified ClientConfiguration interface to use Config() method instead of GetBaseConfig().
- Refactored various client tests to accommodate changes in configuration structure.
- Added new TLS handling functions to support basic and attested TLS configurations.
- Implemented comprehensive tests for TLS loading and configuration validation.
- Removed deprecated methods and unnecessary code related to BaseConfig.

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

---------

Signed-off-by: SammyOina <sammyoina@gmail.com>
Signed-off-by: Sammy Oina <sammyoina@gmail.com>

cmd/agent/main.go

@@ -30,6 +30,7 @@ import (
 	"github.com/ultravioletrs/cocos/pkg/attestation/azure"
 	"github.com/ultravioletrs/cocos/pkg/attestation/tdx"
 	"github.com/ultravioletrs/cocos/pkg/attestation/vtpm"
+	"github.com/ultravioletrs/cocos/pkg/clients"
 	pkggrpc "github.com/ultravioletrs/cocos/pkg/clients/grpc"
 	cvmsgrpc "github.com/ultravioletrs/cocos/pkg/clients/grpc/cvm"
 	"golang.org/x/sync/errgroup"
@@ -111,7 +112,7 @@ func main() {
 		provider = &attestation.EmptyProvider{}
 	}
 
-	cvmGrpcConfig := pkggrpc.CVMClientConfig{}
+	cvmGrpcConfig := clients.StandardClientConfig{}
 	if err := env.ParseWithOptions(&cvmGrpcConfig, env.Options{Prefix: envPrefixCVMGRPC}); err != nil {
 		logger.Error(fmt.Sprintf("failed to load %s gRPC client configuration : %s", svcName, err))
 		exitCode = 1