Add "Network status and alerts" page and RSS feed

[saivann]

This pull request can be previewed live here : http://bitcoinalert.zapto.org/en/alerts

This pull request adds a "Network status and alerts" page on the bottom of the website with a RSS feed to allow people to follow or list network alerts. As well as to see when a network alert is ongoing or not.

Developers can add more alerts in _alerts directory, detailed instructions are in the README
https://github.com/bitcoin/bitcoin.org/tree/alerts#network-alerts

Alerts pages get simple urls such as : bitcoin.org/en/alert/2012-05-14-dos . These urls allow us to translate alerts in the future if we have a responsive team of translators.

[luke-jr]

I think alert pages should always have begin with YYYYMMDD. may15 is which year???

[saivann]

Well it is the right time to redefine this. I can include the date in the url without any problem if needed. I thought that previous alerts url were simple so that they could be remembered easily. However with a visible page on the website, this might not be as much important. YYYY-MM-DD-SHORTTITLE could be a good name.

[gavinandresen]

RE: " bitcoin.org/en/alert/2012-05-14-dos "

Alerts appear as text messages in Bitcoin-Qt (or in the getinfo output from bitcoind), and are not click-able-- users must type them into their web browsers to follow them.

So I'm ok with the canonical URL being something long, as long as they have an as-short-as-possible alias that detects the browser's default language and redirects to the correct page.

[saivann]

@gavinandresen : Is it handy enough to put all alerts in _alerts, and define an optional short alias url in the YAML front matter of each file? Ex : https://github.com/bitcoin/bitcoin.org/tree/alerts#network-alerts