Refactor product filtering and loading for generic scripts

Generic scripts are scripts that handle multiple product based on some identifier (URL, coordinates...).
This creates a common function to list and load product configurations for those scripts.

It makes them simpler to read and maintain, while making the way they work much more consistent.

src/common/endoflife.py

@@ -0,0 +1,27 @@
+import frontmatter
+
+from glob import glob
+from os import path
+
+
+def list_products(method, products_filter=None, pathname = "website/products"):
+    """Return a list of products that are using the same given update method.
+    """
+    products_with_method = {}
+
+    for product_file in glob(f"{pathname}/*.md"):
+        product_name = path.splitext(path.basename(product_file))[0]
+        if products_filter and product_name != products_filter:
+            continue
+
+        with open(product_file, "r") as f:
+            data = frontmatter.load(f)
+            if "auto" in data:
+                configs = list(filter(
+                    lambda config: method in config.keys(),
+                    data["auto"]
+                ))
+                if len(configs) > 0:
+                    products_with_method[product_name] = configs
+
+    return products_with_method