Added and images folder to house images used in static file content. (#20)

* Added an images folder to house images used in static file content.
Since the static https://lucenenet.apache.org/  website is always hosted based on the files in the asf-site branch which is located at https://github.com/apache/lucenenet-site/tree/asf-site it is convenient to place images in the asf-site branch at https://github.com/apache/lucenenet-site/tree/asf-site/images/ once these images are propagates to https://lucenenet.apache.org they can be included in markdown files by using fully qualified image references like https://lucenenet.apache.org/images/my-image.jpg  The advantage of this approach is that when running the DocFx build process on a local dev machine, the static output will be able to render the images handled in this way.

Also added an images/java-lucene-4_8-setup/ folder with lots of images which will be used in a future static page that details how to get Java Lucene 4.8 up and running in a development environment.
80 files changed