Remove links to Oracle Java from install instructions

[khaeru]

We discussed this week that Oracle are harassing organizations for licensing fees, even for individual users who have downloaded and installed the ‘freely’-distributed JRE.

Most current users who have followed the current, ‘simple’ install instructions will have installed OpenJDK, which is free and open source and not subject to these license fees.

However, we still have links to alternate/backup install instructions, and these currently link to (Oracle's) java.com. We should:

1. Remove such links and/or provide recommended alternates.
2. Make users aware that choosing the Oracle JRE are aware of licensing implications.

[glatterf42]

Is this urgent enough to start immediately or should we first wait to figure out which alternatives are best in-house?

[khaeru]

I think because the install instructions have, for some time, recommended an approach that effectively uses OpenJDK, recent new users (even most users) are and will be fine. The more urgent task is to (a) identify users who are still using Oracle Java and (b) help them migrate to something better. That will involve learning about alternatives, whether they work, and how. After that we can make that change (both here and in the ixmp docs).