Add support for textDocument/typeDefinition from XML to XMLSchema/DTD

[angelozerr]

Fix #371

Signed-off-by: azerr azerr@redhat.com

[angelozerr]

You can play with this XSD Type Definition PR, but my code is very ugly. XSD Type definition works with global and local xs:element local and global. xs:attribute is not implemented yet. I will work on it after cleaning my code and writing tests.

Here a demo:

[fbricon]

java.io.FileNotFoundException: /fbricon/.lsp4xml/cache/http/maven.apache.org/xsd/maven-4.0.0.xsd (No such file or directory)
	at java.io.FileInputStream.open0(Native Method)
	at java.io.FileInputStream.open(FileInputStream.java:195)
	at java.io.FileInputStream.<init>(FileInputStream.java:138)
	at com.google.common.io.Files$FileByteSource.openStream(Files.java:129)
	at com.google.common.io.Files$FileByteSource.read(Files.java:153)
	at com.google.common.io.ByteSource$AsCharSource.read(ByteSource.java:470)
	at org.eclipse.lsp4xml.extensions.xsd.contentmodel.CMXSDDocument.findTypeLocation(CMXSDDocument.java:239)
	at org.eclipse.lsp4xml.extensions.contentmodel.participants.ContentModelTypeDefinitionParticipant.findTypeDefinition(ContentModelTypeDefinitionParticipant.java:30)
	at org.eclipse.lsp4xml.services.XMLTypeDefinition.findTypeDefinition(XMLTypeDefinition.java:52)
	at org.eclipse.lsp4xml.services.XMLLanguageService.findTypeDefinition(XMLLanguageService.java:220)
	at org.eclipse.lsp4xml.XMLTextDocumentService.lambda$typeDefinition$15(XMLTextDocumentService.java:321)
	at java.util.concurrent.CompletableFuture.biApply(CompletableFuture.java:1105)
	at java.util.concurrent.CompletableFuture$BiApply.tryFire(CompletableFuture.java:1070)
	at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

[fbricon]

cache location should be /Users/fbricon/.lsp4xml/cache/ instead of /fbricon/.lsp4xml/cache

[angelozerr]

@fbricon please retry this PR. I have written several tests and all are passing. My code should be clean now. Thank's for your review.

[angelozerr]

@fbricon I have rebase my PR and finish to write tests. You can review it when you will have time.