Add download links for supported (and recommended) agent JRE

[reidca]

When you have a large agent install base there will inevitably be a mix of JRE versions since these are often installed along with the agents themselves.

15.2 has seen a lot of problems with older JRE versions not being able to contact the server due to SSL cipher incompatibility issues.

It would be very useful to have a link to the latest (or recommend) JRE for different operating systems that can be installed on the agent machines to ensure the agent can communicate with the server.