Add dependency range info

This commit improves the `info` endpoint to contain a
`dependency-ranges` entry that is similar than the `bom-ranges` entry
for BOMs.

Each dependency that has a version mapping is listed with the range and
the related version. Some dependencies weren't managed and are now. For
those a `managed` version is used to indicate which Spring Boot versions
do not require to specify a version for the dependency.

Closes gh-453

initializr-generator/src/main/java/io/spring/initializr/util/VersionRange.java

@@ -55,6 +55,10 @@ public class VersionRange {
 		this.higherInclusive = higherInclusive;
 	}
 
+	public VersionRange(Version startingVersion) {
+		this(startingVersion, true, null, false);
+	}
+
 	/**
 	 * Specify if the {@link Version} matches this range. Returns {@code true}
 	 * if the version is contained within this range, {@code false} otherwise.

initializr-generator/src/test/java/io/spring/initializr/util/VersionRangeTests.java

@@ -25,6 +25,7 @@ import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
+import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.core.IsNot.not;
 import static org.junit.Assert.assertThat;
 
@@ -36,6 +37,12 @@ public class VersionRangeTests {
 	@Rule
 	public final ExpectedException thrown = ExpectedException.none();
 
+	@Test
+	public void simpleStartingRange() {
+		assertThat(new VersionRange(Version.parse("1.3.0.RELEASE")).toString(),
+				equalTo(">=1.3.0.RELEASE"));
+	}
+
 	@Test
 	public void matchSimpleRange() {
 		assertThat("1.2.0.RC3", match("[1.2.0.RC1,1.2.0.RC5]"));