Add nosearch directive for incomplete scaling docs

[gherceg]

I noticed these docs appeared when searching for "elasticsearch" in commcare-cloud docs. Given these docs are incomplete, we should prevent them from appearing in the search results. Adding the :nosearch: directive seems to do the trick. See https://www.sphinx-doc.org/en/master/usage/restructuredtext/field-lists.html for more info on this directive.

Before:

After:

Environments Affected

None