Minor documentation cleanup

Remove the old changelog and link to a tagged version on GitHub.

Replace outdated jenkins-ci.org with jenkins.io domain name.

Link bug reporting to a page that offers bug, improvement, and security
reporting so that users are encouraged to report issues more accurately
and are encouraged to report security issues in the SECURITY project
rather than the JENKINS project.

Author: MarkEWaite

README.md

@@ -1,9 +1,4 @@
-Git Server Plugin for Jenkins
-=================
-
-[![Jenkins Plugin](https://img.shields.io/jenkins/plugin/v/git-server.svg)](https://plugins.jenkins.io/git-server)
-[![GitHub release](https://img.shields.io/github/release/jenkinsci/git-server-plugin.svg?label=changelog)](https://github.com/jenkinsci/git-server-plugin/releases/latest)
-[![Jenkins Plugin Installs](https://img.shields.io/jenkins/plugin/i/git-server.svg?color=blue)](https://plugins.jenkins.io/git-server)
+# Git Server Plugin for Jenkins
 
 This plugin wraps the server-side functionality of JGit so that other plugins can easily expose
 Git repositories from Jenkins via its SSH transport and HTTP in a collaborative fashion.
@@ -24,12 +19,12 @@ is a convenient default implementation that simplifies this further.
 [GitUserContentRepository](https://github.com/jenkinsci/git-userContent-plugin/blob/master/src/main/java/org/jenkinsci/plugins/gitUserContent/GitUserContentRepository.java)
 in `git-userContent-plugin` is an example of using this class. This use
 also implements
-[RootAction](https://wiki.jenkins-ci.org/display/JENKINS/Action+and+its+family+of+subtypes#Actionanditsfamilyofsubtypes-RootAction)
+[RootAction](https://wiki.jenkins.io/display/JENKINS/Action+and+its+family+of+subtypes#Actionanditsfamilyofsubtypes-RootAction)
 to bind this repository at `http://server/jenkins/userContent.git`, and
 This combination is fairly common.
 
 The other class of interest is [`RepositoryResolver`](https://github.com/jenkinsci/git-server-plugin/blob/master/src/main/java/org/jenkinsci/plugins/gitserver/RepositoryResolver.java).
-Git server plugin adds necessary [Jenkins SSH](https://wiki.jenkins-ci.org/display/JENKINS/Jenkins+SSH) CLI hook for exposing Git repositories over SSH.
+Git server plugin adds necessary [Jenkins SSH](https://wiki.jenkins.io/display/JENKINS/Jenkins+SSH) CLI hook for exposing Git repositories over SSH.
 The only missing link here is that when the client runs `git clone ssh://server/foo/bar/zot.git`,
 we need to figure out what repositories on the server corresponds to `/foo/bar/zot.git`, and that's what the `RepositoryResolver` extension point does.
 [The sample implementation](https://github.com/jenkinsci/git-userContent-plugin/blob/master/src/main/java/org/jenkinsci/plugins/gitUserContent/GitUserContentRepositorySSHAccess.java) in `git-userContent-plugin` will be hopefully self-explanatory.
@@ -38,9 +33,9 @@ In this case, `GitUserContentRepository` is a singleton (because it's `RootActio
 ## Changelog
 
 * See [GitHub Releases](https://github.com/jenkinsci/git-server-plugin/releases/latest) for recent releases
-* See the [Changelog Archive](./docs/OLD_CHANGELOG.md) for versions 1.7 and older
+* See the [Changelog Archive](https://github.com/jenkinsci/git-server-plugin/blob/git-server-1.9/docs/OLD_CHANGELOG.md) for versions 1.7 and older
 
 ## Reporting issues
 
-Use [Jenkins Bugtracker](https://issues.jenkins-ci.org/) to report issues or feature requests
+Use [Jenkins issue tracker](https://www.jenkins.io/participate/report-issue/redirect/#17613) to report issues or feature requests
 (project = `JENKINS`, component = `git-server-plugin`).