docs: Remove building of zipped HTML docs from build process and consequently from Downloads as many users don't use that. We are still providing PDF documentation for people who prefer viewing docs off-line. Removal of this build step is expected to save almost 10 minutes of build time and resolve issue of build failures because of hitting 40 min build time limit on Read The Docs.

.readthedocs.yml

@@ -7,7 +7,6 @@ version: 2
 
 # Optionally build your docs in additional formats such as PDF and ePub
 formats:
-  - htmlzip
   - pdf
 
 # Optionally set the version of Python and requirements required to build your docs