Move emotion to peerDependencies

[emmatown]

What:
Move emotion and babel-plugin-emotion to peerDependencies where they're used in other packages.

This also remove the aliases like emotion/react. emotion/macro and react-emotion/macro are still the entry points for the macros though.

emotion-utils is still a direct dependency.

Why:
it should solve #295.

Right now, emotion is a dependency of emotion-server and others so depending on the way package managers and bundlers do things emotion-server may import emotion from it's own node_modules so it won't have the styles in it's version of emotion.

The same is also true for composition, for example using styled from react-emotion and css from emotion and react-emotion will use emotion from it's node_modules so the styles won't be in the caches.

How:

Checklist:

• Documentation N/A
• Tests N/A
• Code complete

[codecov]

Codecov Report

Merging #322 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #322   +/-   ##
=======================================
  Coverage   96.37%   96.37%           
=======================================
  Files          16       16           
  Lines         580      580           
  Branches      141      141           
=======================================
  Hits          559      559           
  Misses         16       16           
  Partials        5        5

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