Automatically configure formatting for IntelliJ

[pugnascotia]

Forked from #53747.

We could automatically configure IntelliJ to use the Eclipse formatter and our bundled format config. The downside of this is that it relies on the "Eclipse Code Formatter" plugin, though I also noticed a thing in IntelliJ about "Required Plugins", under "Build, Execution, Deployment". I tried adding the Eclipse plugin, and it created the file .idea/externalDependencies.xml with the following content:

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="ExternalDependencies">
    <plugin id="EclipseCodeFormatter" />
  </component>
</project>

Configuring the plugin created: .idea/eclipseCodeFormatter.xml with contents:

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="EclipseCodeFormatterProjectSettings">
    <option name="projectSpecificProfile">
      <ProjectSpecificProfile>
        <option name="formatter" value="ECLIPSE" />
        <option name="pathToConfigFileJava" value="$PROJECT_DIR$/.eclipseformat.xml" />
        <option name="selectedJavaProfile" value="Elasticsearch" />
      </ProjectSpecificProfile>
    </option>
  </component>
</project>

It's also referenced in .idea/workspace.xml:

<project>
  <component name="PropertiesComponent">
    <property name="settings.editor.selected.configurable" value="EclipseFormatter" />

[elasticmachine]

Pinging @elastic/es-core-infra (:Core/Infra/Build)

[mark-vieira]

@pugnascotia does the recent work for Checkstyle mostly address this?

[pugnascotia]

No, this is a separate thing.

[mark-vieira]

Where did we land with this? So far as I can tell the only missing bit is the "Required plugins" bit. I tested this locally by uninstalling the plugin and doing a fresh import and it worked fine.

I suggest we go ahead and do this so it's one less thing folks have to configure manually. In fact, I think that will mean folks don't have to configure anything manually on import which would be awesome. I know we've had some reports of folks fighting with spotless before realizing they weren't using the same format rules in the IDE.

[pugnascotia]

I haven't looked at this again since I raised it, but if you can get it to work on project import then please do!

[mark-vieira]

Should we add the checkstyle plugin to the list as well?