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Update wiki.less: fix showfor padding

I added 10px padding (right and left) for .selectbox class, to make the texts displayed in the Select input boxes for OS and Mozilla Version in KB articles.

Example

Open the below link you can find 2 select box right to the firefox logo above editing tools option.
https://support.mozilla.org/en-US/kb/firefox-takes-long-time-start-up
[Bug 906992] Set up multiple ES index framework.

Now settings.py can contain multiple indexes in ES_INDEXES and/or
ES_WRITE_INDEXES, and models can choose which kind of index to use. The
admin and management commands have been updated, and I updated search
and other parts of the site that use elastic to account for multiple
indexes, where needed.