feat: add proof-of-concept high availability cluster config

[amcgee]

No description provided.

[bobjolliffe]

Nice work. A few small improvements on server,xml

1. -- replace with shutdown="-1". You are opening a control port unnecessarily, also with a well known cleartext password. Just simplify and get rid of it :-)
2. Get rid of the ajp connector. I don't think it is being used
3. In production we wouldn't usually have unpackWars=true. In fact better to just provide tomcat with readonly access to the unpacked webapp. It might be reasonable enough to do it this way for the POC, but if you want to get closer to production ready (people will copy and run this!) it might be worth to implement it this way.

[amcgee]

@bobjolliffe thanks! Is this more or less what you meant?

0c2695b

[amcgee]

@Philip-Larsen-Donnelly pointed out that this probably needs to be extended with a shared logical volume for the file store