Move Docs Navigation to the Left Side of Pages

[nate-double-u]

Similar to https://github.com/dexidp/website/issues/56

As per https://dexidp.io/ feedback session, bring navigation to left side of documentation pages to be consistent with the rest of the CNCF landscape.

Things related to this shift:

• The Edit on GitHub button may become incorrectly placed. Similar to https://github.com/dexidp/website/issues/64
• The panel being on the left may become too wide. Similar to https://github.com/dexidp/website/issues/63

[kapunahelewong]

Closed by #73