.editorconfig for ktlint.

[uk-taniyama]

• set .editorconfig fullpath: then use it.
  ktlint().userData([editorconfig: project.file(".editorconfig").absolutePath])

• set "?": recursively search the closest .editorconfig
  ktlint().userData([editorconfig: "?"])

[nedtwigg]

Thanks for a first shot at implementing #142. As noted in that issue, you need to capture the state of the .editorconfig file because this PR would break up-to-date checking as currently written.

Here's an example

spotless/lib/src/main/java/com/diffplug/spotless/scala/ScalaFmtStep.java

Lines 70 to 84 in eb22218

	final FileSignature configSignature;
	State(String version, Provisioner provisioner, @Nullable File configFile) throws IOException {
	String mavenCoordinate;
	Matcher versionMatcher;
	if ((versionMatcher = VERSION_PRE_2_0.matcher(version)).matches()) {
	mavenCoordinate = MAVEN_COORDINATE_PRE_2_0;
	} else if ((versionMatcher = VERSION_PRE_3_0.matcher(version)).matches()) {
	mavenCoordinate = MAVEN_COORDINATE_PRE_3_0;
	} else {
	mavenCoordinate = MAVEN_COORDINATE;
	}
	this.jarState = JarState.from(mavenCoordinate + version, provisioner);
	this.configSignature = FileSignature.signAsList(configFile == null ? Collections.emptySet() : Collections.singleton(configFile));

[nedtwigg]

The new stuff you pushed doesn't address my comment above. Very happy to merge something which fixes the .editorconfig issue, but in the future please don't force-push. Sloppy commits are fine, it's easier to review the changes without force-push.

[nedtwigg]

I think that #1218 makes this unnecessary.