Add an html validator to CI pipeline

[duker33]

Created from #849

[olegush]

@duker33 , I do not see file breadcrumbs_with_siblings.html in the repo

[duker33]

@olegush , breadcrumbs_with_siblings.html is not needed there. The task is to add django templates validation pipeline step. It should validate every django html template.

Try to find some existing django templates validation lib