Customize validations for the OIDCAgentConfig.

**Description:**
Add Validator implementations in the SDK for validating the Agent Config in order to add customizable validations and enforcement.
```
public Interface Validator {

void validate(OIDCAgentConfig config);
}
```
validators - CodeValidator, LogoutValidator, ImplicitValidator, etc.

```
public OIDCManagerImpl(OIDCAgentConfig oidcAgentConfig, Validator[] validators) throws SSOAgentClientException {

for (Validator validator: validators) {
validator.validate(oidcAgentConfig);
}
this.oidcAgentConfig = oidcAgentConfig;
}
```

Start by locating OIDCAgentConfig and OIDCManagerImpl, then inspect how configuration validation currently occurs. Review the requested Validator interface and the listed validator types to understand the intended scope. Done means customizable validators can be applied when constructing OIDCManagerImpl and enforce the agent configuration.

Written by the indexing model from the issue text.