implement obtaining ST from ST

internal/endpoints/token/access/accessTokenEndpoint.go

internal/endpoints/token/super/pkg/superTokenRequest.go

internal/endpoints/token/super/polling/pollingEndpoint.go

internal/endpoints/token/super/supertokenEndpoint.go

internal/model/apiError.go

internal/model/grantType.go

internal/model/response.go

internal/oidc/authcode/authcode.go

internal/supertoken/capabilities/capability.go

internal/supertoken/capabilities/capability_test.go

internal/supertoken/pkg/supertoken_test.go

internal/supertoken/restrictions/restriction_test.go

internal/supertoken/superTokenHandler.go

internal/supertoken/supertokenEntry.go

internal/utils/ctxUtils/grantType.go

internal/utils/dbUtils/dbUtils.go