* Remove six for PY2 compatability since our dependencies are not, PY2
is legacy.
* Removed usages of utils from future/past libraries since they are
deprecated. This includes 'from __future__ ...' and 'from past...'
statements.
* Removed compatibility imports for PY2, switched from six imports to
standard library imports.
* Removed utils code blocks that handle operations depending on PY2/3
versions.
* Removed 'from __future__ ...' lines from templates/code generators
* Used PY3 syntaxes in place of PY2 compatible blocks. eg: metaclass
* [domainify] hide restrict to domain modules from modules page
* [minor] cleared the domainification cache and other minor fixes
* Update test_domainification.py
* [feature] domainify doctype, pages and roles
* [minor] added get active domain method to __init__
* [fixes] minor fixes in domainification and added test cases
* [minor] added checkbox-editor class to render the domains
* [minor] added checkbox_selector option
* [minor] added or_filters to filter restrict to domain doctype and roles
* [minor] fixed codacy errors
