refactor: Restructure the fetchers code to not use more memory than needed

Also fixes: #92

scrapling/fetchers/__init__.py

@@ -0,0 +1,36 @@
+from typing import TYPE_CHECKING, Any
+
+if TYPE_CHECKING:
+    from scrapling.fetchers.requests import Fetcher, AsyncFetcher, FetcherSession
+    from scrapling.fetchers.chrome import DynamicFetcher, DynamicSession, AsyncDynamicSession
+    from scrapling.fetchers.firefox import StealthyFetcher, StealthySession, AsyncStealthySession
+
+
+# Lazy import mapping
+_LAZY_IMPORTS = {
+    "Fetcher": ("scrapling.fetchers.requests", "Fetcher"),
+    "AsyncFetcher": ("scrapling.fetchers.requests", "AsyncFetcher"),
+    "FetcherSession": ("scrapling.fetchers.requests", "FetcherSession"),
+    "DynamicFetcher": ("scrapling.fetchers.chrome", "DynamicFetcher"),
+    "DynamicSession": ("scrapling.fetchers.chrome", "DynamicSession"),
+    "AsyncDynamicSession": ("scrapling.fetchers.chrome", "AsyncDynamicSession"),
+    "StealthyFetcher": ("scrapling.fetchers.firefox", "StealthyFetcher"),
+    "StealthySession": ("scrapling.fetchers.firefox", "StealthySession"),
+    "AsyncStealthySession": ("scrapling.fetchers.firefox", "AsyncStealthySession"),
+}
+
+__all__ = ["Fetcher", "AsyncFetcher", "StealthyFetcher", "DynamicFetcher"]
+
+
+def __getattr__(name: str) -> Any:
+    if name in _LAZY_IMPORTS:
+        module_path, class_name = _LAZY_IMPORTS[name]
+        module = __import__(module_path, fromlist=[class_name])
+        return getattr(module, class_name)
+    else:
+        raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
+
+
+def __dir__() -> list[str]:
+    """Support for dir() and autocomplete."""
+    return sorted(list(_LAZY_IMPORTS.keys()))