Remove "int-he" and replace "int-en" with "lang-font" class

[lobsam]

Description :

Sefaria has put in place in template file or in react, only two language system (ie; english and hebrew). And adding new languages makes it complicated.

for an example :

                            <span class="int-en">{% trans "Add Source Title" %}</span>
                            <span class="int-he">{% trans "Add Source Title" %}</span>

if pecha.org is switch to english, styled int-he makes hebrew(tibetan) language invisible. But when add new language
(eg;chinese) then both strings get shown. and to solve it adding int-zh class would be impossible for adding future languages.

So the only option is to delete the int-he contained line and replace int-en class with lang-font class name. And replace in css int-en class to lang-font so that applied font-family wouldn't get effected.

This would make possible for adding more languages without any issue and remove the two language system from pecha.org.

Implementation steps:

• Remove existing "int-he" class for all the strings and replace all the "int-en" with "lang-font" class both in django template.

• Apply lang-font class in css for font-family and other avail styling.