This adds a generated-resources dir that the plugin properties are
generated into. This must be outside of the build dir, since intellij
has build as "excluded".
closes#14392
When generating a try-catch block, the eclipse default is something like this:
```
try {
something();
} catch (Exception e) {
// TODO: auto-generated stub
e.printStackTrace();
}
which is terrible, so the ES eclipse changes this to rethrow a RuntimeException instead.
```
try {
something();
} catch (Exception e) {
throw new RuntimeException();
}
```
Unfortunately, this loses the original exception entirely, instead it should be:
```
try {
something();
} catch (Exception e) {
throw new RuntimeException(e);
}
```
The RR gradle plugin is at
https://github.com/randomizedtesting/gradle-randomized-testing-plugin.
However, we currently have a copy of this, since the plugin is still in
heavy development. This change moves the files around so they can be
copied directly from the elasticsearch fork to that repo, for ease of
syncing.