Move site_vars to templates/site_vars.html

[calismu]

Closes #13

[kjaymiller]

@calismu - LGTM

Let me get #18 figured out so I can test that the template builds as expected.

[john0isaac]

@kjaymiller I think we agreed that it's better to separate the site_vars into a separate file and calling it settings.py as it's taking lots of space in the app.py

settings.py

SITE_VARS = {
...
} 

and in app.py
import SITE_VARS from settings

and app.site_vars.update(SITE_VARS)

This PR only separates them in rendering but after cookiecutter resolves it it's the same output.

[kjaymiller]

@john0isaac - I think this can still be merged and we can add the additional structure in a separate PR.

[kjaymiller]

@calismu #19 was approved so this should be merged in the near future.

[john0isaac]

@calismu can you rebase your branch so the tests run? if the tests pass successfully we will merge the PR