Friendly down page for otc.skycoin.net

[nutmix]

Currently, when you click on the "Buy Skycoin directly with BTC" on the https://www.skycoin.net/markets/ page, you get the following error:

This site can’t be reached
otc.skycoin.net refused to connect.
Try:

Checking the connection
Checking the proxy and the firewall
ERR_CONNECTION_REFUSED

This could be very damaging - it makes us look like we do not know what we are doing for anyone who checks.

As a quick fix, we should have a friendly down page for OTC which says something like:

We are currently developing the next generation teller application for skycoin.  
In the mean time, please use one of these services to purchase skycoin
  =>  c2cx 
etc.

To put this live, we could either:

1. change the link on the markets page (wont work for bookmarks and search pages)
2. setup a redirect of any page to the new down page using the hosting control panel (e.g. cloudflare, Amazon S3 etc) or a htaccess or similar if the site is hosted on a real webserver.
3. replace the current index page on the otc server.

A second later phase of this would be for the skycoin.net page to check the status of the otc server and not put the link there if it is down (instead give a friendly message).

[gz-c]

Can do this now that #196 is merged

[gz-c]

I put it back up in "closed" status, https://otc.skycoin.net