infra: new api end point to generate and get index.html content

[peterpeterparker]

Affected part of DeckDeckGo

• Infra
• Cloud

Feature Description

As already discussed, it would be useful to create a new infra end point which basically process all the publish steps of parsing, including the calculation of the js hash, and, instead of writing the presentation in a bucket and deploying it only, would "just" return the content of the generated index.html.

Use Case

This would allow us to generate a "push anytime to GitHub" feature but, more important, will speed up the first publish if user select both "publish online and github" because I had to implement a delay as the known workaround "wait until cloudfront is populated".

[peterpeterparker]

moreover than the feature "push to github" this can maybe also be interesting to add a "backup" option as suggested in #1015 (download a local copy to not loose text)

UPDATE: actually maybe not for backup, because we also need a backup of the offline data (in case shit happens so the local cache can be wiped out to go back online)