Make device initialisation easier by reducing required imports (#936)

Adds username and password arguments to discovery to remove the need to import Credentials.
Creates TypeAliases in Device for connection configuration classes and DeviceType.
Using the API with these changes will only require importing either Discover or Device
depending on whether using Discover.discover() or Device.connect() to 
initialize and interact with the API.

kasa/deviceconfig.py

@@ -5,11 +5,11 @@ via discovery or connect directly with :class:`DeviceConfig`.
 
 Discovery returns a list of discovered devices:
 
->>> from kasa import Discover, Credentials, Device, DeviceConfig
+>>> from kasa import Discover, Device
 >>> device = await Discover.discover_single(
 >>>     "127.0.0.3",
->>>     credentials=Credentials("myusername", "mypassword"),
->>>     discovery_timeout=10
+>>>     username="user@example.com",
+>>>     password="great_password",
 >>> )
 >>> print(device.alias)  # Alias is None because update() has not been called
 None
@@ -21,7 +21,7 @@ None
 : {'device_family': 'SMART.TAPOBULB', 'encryption_type': 'KLAP', 'login_version': 2},\
  'uses_http': True}
 
->>> later_device = await Device.connect(config=DeviceConfig.from_dict(config_dict))
+>>> later_device = await Device.connect(config=Device.Config.from_dict(config_dict))
 >>> print(later_device.alias)  # Alias is available as connect() calls update()
 Living Room Bulb
 
@@ -45,7 +45,7 @@ if TYPE_CHECKING:
 _LOGGER = logging.getLogger(__name__)
 
 
-class EncryptType(Enum):
+class DeviceEncryptionType(Enum):
     """Encrypt type enum."""
 
     Klap = "KLAP"
@@ -53,7 +53,7 @@ class EncryptType(Enum):
     Xor = "XOR"
 
 
-class DeviceFamilyType(Enum):
+class DeviceFamily(Enum):
     """Encrypt type enum."""
 
     IotSmartPlugSwitch = "IOT.SMARTPLUGSWITCH"
@@ -105,11 +105,11 @@ def _dataclass_to_dict(in_val):
 
 
 @dataclass
-class ConnectionType:
+class DeviceConnectionParameters:
     """Class to hold the the parameters determining connection type."""
 
-    device_family: DeviceFamilyType
-    encryption_type: EncryptType
+    device_family: DeviceFamily
+    encryption_type: DeviceEncryptionType
     login_version: Optional[int] = None
 
     @staticmethod
@@ -117,12 +117,12 @@ class ConnectionType:
         device_family: str,
         encryption_type: str,
         login_version: Optional[int] = None,
-    ) -> "ConnectionType":
+    ) -> "DeviceConnectionParameters":
         """Return connection parameters from string values."""
         try:
-            return ConnectionType(
-                DeviceFamilyType(device_family),
-                EncryptType(encryption_type),
+            return DeviceConnectionParameters(
+                DeviceFamily(device_family),
+                DeviceEncryptionType(encryption_type),
                 login_version,
             )
         except (ValueError, TypeError) as ex:
@@ -132,7 +132,7 @@ class ConnectionType:
             ) from ex
 
     @staticmethod
-    def from_dict(connection_type_dict: Dict[str, str]) -> "ConnectionType":
+    def from_dict(connection_type_dict: Dict[str, str]) -> "DeviceConnectionParameters":
         """Return connection parameters from dict."""
         if (
             isinstance(connection_type_dict, dict)
@@ -141,7 +141,7 @@ class ConnectionType:
         ):
             if login_version := connection_type_dict.get("login_version"):
                 login_version = int(login_version)  # type: ignore[assignment]
-            return ConnectionType.from_values(
+            return DeviceConnectionParameters.from_values(
                 device_family,
                 encryption_type,
                 login_version,  # type: ignore[arg-type]
@@ -180,9 +180,9 @@ class DeviceConfig:
     #: The protocol specific type of connection.  Defaults to the legacy type.
     batch_size: Optional[int] = None
     #: The batch size for protoools supporting multiple request batches.
-    connection_type: ConnectionType = field(
-        default_factory=lambda: ConnectionType(
-            DeviceFamilyType.IotSmartPlugSwitch, EncryptType.Xor, 1
+    connection_type: DeviceConnectionParameters = field(
+        default_factory=lambda: DeviceConnectionParameters(
+            DeviceFamily.IotSmartPlugSwitch, DeviceEncryptionType.Xor, 1
         )
     )
     #: True if the device uses http.  Consumers should retrieve rather than set this
@@ -195,8 +195,8 @@ class DeviceConfig:
 
     def __post_init__(self):
         if self.connection_type is None:
-            self.connection_type = ConnectionType(
-                DeviceFamilyType.IotSmartPlugSwitch, EncryptType.Xor
+            self.connection_type = DeviceConnectionParameters(
+                DeviceFamily.IotSmartPlugSwitch, DeviceEncryptionType.Xor
             )
 
     def to_dict(