who wants some nginx?

[Andrew Geissler]

I picked up some commits from Chris that enabled Nginx in OpenBMC.  We
want  it for a few reasons:

- It provides an easy mechanism to redirect http to https (i.e. user
just types <bmc ip> and get redirected to https which then auto loads
the GUI
- It gives us flexibility to serve multiple back end servers off the
https port (or any port)
- It's much faster then our current front end server
- Many other cool feature we may use some day

https://gerrit.openbmc-project.xyz/#/c/6879/

The question is do we enable for all openbmc systems or just ours?
Any votes?  Feel free to comment the review with your thoughts.

It looks like it takes up about an additional ~250KB of flash space.
There is no impact to our existing REST api path with this change.

Andrew