Active Proxy Support

[ftclausen]

Hello,

This PR allows proxy installation, auto registration with server and the means by which Zabbix agents can be associated with a particular proxy at node registration time (or subsequently at node update time). The usage is documented in the README under the Proxy section. I am currently using this with success at my employer and it makes managing many proxies more consistent and migrating agents to a particular proxy can be done automatically.

I realise this is quite a big PR and some of the highlights are

• Only active proxies are currently supported
• Building the proxy and server is almost exactly the same so create common _server_common_build_deps.rb recipe used by both server and the proxy
• Added in some Java gateway fixes (not directly related to proxy but noticed them during testing)
• Determining the correct proxy for a given Zabbix agent to use is something that needs to be figured out in a wrapper cookbook - this is not something we can guess since many companies will have different criteria.
• Only installation of source is currently supported

Tested on Debian and RHEL but more testing "in the wild" needed.

Any feedback welcome.

[guilhem]

Hi @ftclausen Thanks for this PR. I'm OK for this one if this doesn't break other usage (tested by TK) and if you are adding some new TK tests ;)

[ftclausen]

Thanks - I will definitely add some TK tests.

[guilhem]

@ftclausen poke me if it's done or if you need some help