This removes all the mentions of the sandbox from the script engine
services and permissions model. This means that the following settings
are no longer supported:
```yaml
script.inline: sandbox
script.stored: sandbox
```
Instead, only a `true` or `false` value can be specified.
Since this would otherwise break the default-allow parameter for
languages like expressions, painless, and mustache, all script engines
have been updated to have individual settings, for instance:
```yaml
script.engine.groovy.inline: true
```
Would enable all inline scripts for groovy. (they can still be
overridden on a per-operation basis).
Expressions, Painless, and Mustache all default to `true` for inline,
file, and stored scripts to preserve the old scripting behavior.
Resolves#17114
* Reorganize scripting documentation
* Further changes to tidy up scripting docs
Closes#18116
* Add note about .lat/lon potentially returning null
* Added .value to expressions example
* Fixed two bad ASCIIDOC links
This commit adds a new configuration file jvm.options to centralize and
simplify management of JVM options. This separates the configuration of
the JVM from the packaging scripts (bin/elasticsearch*, bin/service.bat,
and init.d/elasticsearch) simplifying end-user operational management of
custom JVM options.
2.x has show so far that running with security manager is the way to go.
This commit make this non-optional. Users that need to pass their own rules
can still do this via the system configuration for the security manager. They
can even opt out of all security that way.