chore(storage-boxes): add experimental markers to all clients and methods (#604)

I added the `Experimental` markers as described in
https://hcloud-python.readthedocs.io/en/stable/#experimental-features

I saw that for DNS we only marked the methods. The docs specify that
classes should also be marked, so I added it to the clients too.

Author: apricote

hcloud/storage_box_types/client.py

@@ -25,6 +25,9 @@ class StorageBoxTypesClient(ResourceClientBase):
     A client for the Storage Box Types API.
 
     See https://docs.hetzner.cloud/reference/hetzner#storage-box-types.
+
+    Experimental:
+        Storage Box support is experimental, breaking changes may occur within minor releases.
     """
 
     _base_url = "/storage_box_types"
@@ -40,6 +43,9 @@ def get_by_id(self, id: int) -> BoundStorageBoxType:
         See https://docs.hetzner.cloud/reference/hetzner#storage-box-types-get-a-storage-box-type
 
         :param id: ID of the Storage Box Type.
+
+        Experimental:
+            Storage Box support is experimental, breaking changes may occur within minor releases.
         """
         response = self._client.request(
             method="GET",
@@ -54,6 +60,9 @@ def get_by_name(self, name: str) -> BoundStorageBoxType | None:
         See https://docs.hetzner.cloud/reference/hetzner#storage-box-types-list-storage-box-types
 
         :param name: Name of the Storage Box Type.
+
+        Experimental:
+            Storage Box support is experimental, breaking changes may occur within minor releases.
         """
         return self._get_first_by(self.get_list, name=name)
 
@@ -71,6 +80,9 @@ def get_list(
         :param name: Name of the Storage Box Type.
         :param page: Page number to return.
         :param per_page: Maximum number of entries returned per page.
+
+        Experimental:
+            Storage Box support is experimental, breaking changes may occur within minor releases.
         """
         params: dict[str, Any] = {}
         if name is not None:
@@ -102,6 +114,9 @@ def get_all(
         See https://docs.hetzner.cloud/reference/hetzner#storage-box-types-list-storage-box-types
 
         :param name: Name of the Storage Box Type.
+
+        Experimental:
+            Storage Box support is experimental, breaking changes may occur within minor releases.
         """
         return self._iter_pages(
             self.get_list,