Replace gitweb glue with WebLink extensions

Keep the gitweb configuration section, but bind the URLs through the
WebLink extension points instead of specific support in the web UI.
This simplifies the server and UI implementations a bit by using
only code paths that other plugins like the gitiles plugin use.

Change-Id: I8508dcaf3a4405b3ce3a47f2f717472a46e5a8ca

gerrit-common/src/main/java/com/google/gerrit/common/data/GitwebType.java

@@ -26,7 +26,6 @@ public class GitwebType {
   private String rootTree;
 
   private char pathSeparator = '/';
-  private boolean linkDrafts = true;
   private boolean urlEncode = true;
 
   /** @return name displayed in links. */
@@ -141,20 +140,6 @@ public class GitwebType {
     this.pathSeparator = separator;
   }
 
-  /** @return whether to generate links to draft patch sets. */
-  public boolean getLinkDrafts() {
-    return linkDrafts;
-  }
-
-  /**
-   * Set whether to generate links to draft patch sets.
-   *
-   * @param linkDrafts new value.
-   */
-  public void setLinkDrafts(boolean linkDrafts) {
-    this.linkDrafts = linkDrafts;
-  }
-
   /** @return whether to URL encode path segments. */
   public boolean getUrlEncode() {
     return urlEncode;