Build Web Staff Client and Websocketd

Build Web Staff Client and Websocketd

Modify the SSL README file to show how to combine the server
certificate and chain files into 1 file for websocketd and apache.

Add steps to script/postbuild.sh to write steps for web staff client
and websocketd to the buildeg.sh script:

1. Add ubuntu-$EGVMSUITE-developer target to Evergreen prerequisite
   installation.

2. Add web client JS installation steps.

3. Add eg2 Angular installation steps if the directory is present.

4. Download, install, and start websocketd.

Signed-off-by: Jason Stephenson <jason@sigio.com>