Add .readthedocs.yaml

It is now mandatory
https://blog.readthedocs.com/migrate-configuration-v2/

Also fixes empty app library in rtd.

Signed-off-by: Francesco Gazzetta <fgaz@fgaz.me>

.readthedocs.yaml

@@ -0,0 +1,20 @@
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+version: 2
+
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3"
+  jobs:
+    pre_build:
+      # Ensure appregistry is generated
+      - ./tools/configure_wasp_apps.py wasp.toml
+
+python:
+  install:
+    - requirements: docs/requirements.txt
+
+sphinx:
+  configuration: docs/conf.py

docs/requirements.txt

@@ -0,0 +1 @@
+tomli

tools/configure_wasp_apps.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 """Configure the wasp distribution based on the provided wasp.toml config
 
     This script generates the following files and directories