Hindi translation

[milancurcic]

The weblate language code is hi.

[kritikarag]

Hi @milancurcic can you assign this issue to me?(I've been working on this remotely)

[kritikarag]

Hello, these are the following changes that I've made
Committed changes are as follows:

• created .po files in locale/in.
• translated all the .po files into Hindi.
• added 'in' like {%- for lang in ('zh_CN', 'de', 'en', 'es', 'fr', 'ja', 'nl,'in') %} in pages/_templates/sbt-sidebar-footer.html.
• added in to LANGUAGE in Makefile.

Is there anything else I need to do before creating a pull request?

P.S. - Really sorry I took a little more time to complete this task