Refactor document-list macros to suit Jinja2 templates

[SriHV]

While testing nunjucks files in Jinja Environment(as part of the #3086), few examples showed ‘internal server error’. The main cause of this issue is the differences between Nunjucks (a templating language in JS environments and DS) and Jinja2 (a templating language used by flask in python). Macros need refactoring so it can suit Jinja2 template. This was addressed previously in #3080.

The errors are split up to simplify while refactoring.

components/document-list/example-document-list-downloads.njk threw error jinja2.exceptions.UndefinedError: 'list object' has no attribute 'push' : This is due to push, as a function, not identified by the lists in python. Document-list needs refactoring