Move transports into their own package (#1247)

This moves all transport implementations into a new `transports` package
for cleaner main package & easier to understand project structure.

kasa/transports/__init__.py

@@ -0,0 +1,16 @@
+"""Package containing all supported transports."""
+
+from .aestransport import AesEncyptionSession, AesTransport
+from .basetransport import BaseTransport
+from .klaptransport import KlapTransport, KlapTransportV2
+from .xortransport import XorEncryption, XorTransport
+
+__all__ = [
+    "AesTransport",
+    "AesEncyptionSession",
+    "BaseTransport",
+    "KlapTransport",
+    "KlapTransportV2",
+    "XorTransport",
+    "XorEncryption",
+]