Remove invalid releases automatically (#466)

Automatically remove empty releases or releases which are released in the future, regardless of the product.

Also refactored a bit releasedata.py to use better names and clarify types.

releases/nutanix-prism.json

@@ -1,78 +1,5 @@
 {
-  "releases": {
-    "pc.2024.3": {
-      "name": "pc.2024.3"
-    },
-    "pc.2024.2": {
-      "name": "pc.2024.2"
-    },
-    "pc.2024.1": {
-      "name": "pc.2024.1"
-    },
-    "pc.2023.4": {
-      "name": "pc.2023.4"
-    },
-    "pc.2023.3": {
-      "name": "pc.2023.3"
-    },
-    "pc.2023.1": {
-      "name": "pc.2023.1"
-    },
-    "pc.2022.9": {
-      "name": "pc.2022.9"
-    },
-    "pc.2022.6": {
-      "name": "pc.2022.6"
-    },
-    "pc.2022.4": {
-      "name": "pc.2022.4"
-    },
-    "pc.2022.1": {
-      "name": "pc.2022.1"
-    },
-    "pc.2021.9": {
-      "name": "pc.2021.9"
-    },
-    "pc.2021.8": {
-      "name": "pc.2021.8"
-    },
-    "pc.2021.7": {
-      "name": "pc.2021.7"
-    },
-    "pc.2021.5": {
-      "name": "pc.2021.5"
-    },
-    "pc.2021.3": {
-      "name": "pc.2021.3"
-    },
-    "pc.2021.1": {
-      "name": "pc.2021.1"
-    },
-    "pc.2020.9": {
-      "name": "pc.2020.9"
-    },
-    "pc.2020.8": {
-      "name": "pc.2020.8"
-    },
-    "pc.2020.7": {
-      "name": "pc.2020.7"
-    },
-    "pc.2020.11": {
-      "name": "pc.2020.11"
-    },
-    "5.17": {
-      "name": "5.17"
-    },
-    "5.16": {
-      "name": "5.16"
-    },
-    "5.11": {
-      "name": "5.11"
-    },
-    "5.10": {
-      "name": "5.10"
-    }
-  },
+  "releases": {},
   "versions": {
     "pc.2024.3.1.4": {
       "name": "pc.2024.3.1.4",