Host the Doxygen documentation on readthedocs

The documentation will be located at:
https://longturn.readthedocs.io/en/latest/Playing/index.html

.readthedocs.yaml

@@ -8,6 +8,13 @@ build:
   os: ubuntu-22.04
   tools:
     python: "3.10"
+  jobs:
+    pre_build:
+      # Creates the documentation in the doxygen/ subfolder
+      - doxygen
+    post_build:
+      # Move the output to be hosted
+      - mv doxygen/html $READTHEDOCS_OUTPUT/html/Doxygen
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx: