Empty completion after an error from microprofile/projectInfo

[angelozerr]

When completion (or other feature like validation, hover, etc) is called it consume the JDT LS microprofile/projectInfo
to collect properties. When microprofile/projectInfo throws an error and completion is redone, the properties are empty, even if
classpath changed.

This poblem occurs because of this fix (when application.properties doesn't belong to a Java project). The fix cache the completable future after
CompletableFuture.exceptions is called (when error is catch). The completable future which must be cached must be done before the exception is cacth
(before CompletableFuture.exceptions is called).

By doing that, we need to fix the case of application.properties doesn't belong to a Java project which must retun an empty project info
instead of throwing an error, otherwise, it will call every time the JDT LS extension microprofile/projectInfo each time completion is triggered
(should not be done since application.properties doesn't belong to a Java project).

An another case is when application.properties belongs to an Eclipse project but not in Java project. The JDT LS extension must return a project info with
the proper project location uri. By doing that, when user add a pom.xml, a classpath changed will be fired and a microprofile/propertiesChanged will be fired
and MicroProfile LS will reload the properties.