Wrong Languages % in the index chart

[pbrudnick]

There's a bug with the languages percentage for all the orgs (/api/languages):

1. The calculation is being done with bytes, we should use the sum of org percentages.
   So, it does not affect if there is a repo with a LOT of bytes of one language, instead of the percentage of that language in the org.
2. The GitLab API retrieves language percentages and not bytes, so the number of bytes couldn't be used to calculate totals anymore.

Proposed solution:

• Calculate the total of lang % using the aggregation of org lang %.
• Get rid of bytes where it is not needed.
• Fix the index chart with the languages accumulating the org percentages (it will be impacted in react models, etc)