Make our infrastructure more redundant

Originally created by @intrigeri on #16956 (Redmine)

Problems we already know about:

• it would be nice to be able to reboot lizard without people suffering from the Tails website being down;
• DDoS resistance: we’re in a very bad place when lizard or SeaCCP are DDoS’ed.

So at least we would like to make our website hosted in more than one location. Hosting our website elsewhere too might require dropping the ikiwiki cgi, which itself requires:

• move blueprints out to a separate wiki
• switch to an external search engine
• replace our usage of the ikiwiki ping plugin with something else

Depending on the outcome of the risk analysis, there’s probably things we should make more redundant, if this fits into our 2019-2020 sysadmin budget.

Related issues

• Related to tails#12406
• Blocked by #15097