Use consistent lowercase for "gitweb"

We had inconsistent class and variable naming in Gerrit to the point
that (prior to I640e645f6) there were two completely different classes
named "GitwebConfig" and "GitWebConfig".

In the official upstream Git documentation, this command line tool is
most often referred to as "gitweb". Standardize on this
capitalization in text. It may still be capitalized at the beginning
of sentences, or where required by programming language style (e.g.
Java class names).

The only exceptions are:
 - MSysGit's wiki page is entitled GitWeb, so use that when referring
   specifically to that page.
 - Old release notes were not touched.

Change-Id: I497477c264e9cc1380c520618f8edf13e7226c9d

gerrit-common/src/test/java/com/google/gerrit/common/data/EncodePathSeparatorTest.java

@@ -21,14 +21,14 @@ import org.junit.Test;
 public class EncodePathSeparatorTest {
   @Test
   public void testDefaultBehaviour() {
-    assertEquals("a/b", new GitWebType().replacePathSeparator("a/b"));
+    assertEquals("a/b", new GitwebType().replacePathSeparator("a/b"));
   }
 
   @Test
   public void testExclamationMark() {
-    GitWebType gitWebType = new GitWebType();
-    gitWebType.setPathSeparator('!');
-    assertEquals("a!b", gitWebType.replacePathSeparator("a/b"));
+    GitwebType gitwebType = new GitwebType();
+    gitwebType.setPathSeparator('!');
+    assertEquals("a!b", gitwebType.replacePathSeparator("a/b"));
   }
 
 }