Restructure "registry" modules

tests/commands/test_lib.py

@@ -21,10 +21,10 @@ import pytest
 import semantic_version
 
 from platformio.commands.lib.command import cli as cmd_lib
-from platformio.package.client import RegistryClient
 from platformio.package.meta import PackageType
 from platformio.package.vcsclient import VCSClientFactory
 from platformio.project.config import ProjectConfig
+from platformio.registry.client import RegistryClient
 
 
 def test_saving_deps(clirunner, validate_cliresult, isolated_pio_core, tmpdir_factory):

tests/misc/test_misc.py

@@ -18,7 +18,7 @@ import pytest
 import requests
 
 from platformio import __check_internet_hosts__, http, proc
-from platformio.package.client import RegistryClient
+from platformio.registry.client import RegistryClient
 
 
 def test_platformio_cli():