Produced HTMLs should be removed from git

[anton-trunov]

Tons of changes after recompilation in the generated HTML files make it harder to review PRs in this repo, so these should be removed and added to .gitignore.

[chiliec]

It can be done by using GitHub Actions to transfer the HTML from the main branch to the gh-pages branch. When new changes are made to the main branch, the HTML is compiled and pushed to the gh-pages branch. For example, as demonstrated in this example: https://gist.github.com/umanghome/30527c68cd605dfef8702a832ff14fd5

However, it is necessary to change the Pages settings in the repository's Settings.