Move Javascript found in server.rb to a new home

This PR moves all the JavaScript found in lib/msf/core/exploit/http/server.rb to multiple .js files in data/js.  These functions include:

* js_base64
* js_ajax_download
* js_mstime_malloc
* js_property_spray
* js_heap_spray
* js_os_detect
* addons detections

To test, you can use the following script:
https://gist.github.com/wchen-r7/7047590

You can also run these browser exploit modules:

* ie_cbutton_uaf can test the js_mstime_malloc function
* ms13_080_cdisplaypointer can test js_base64, js_property_spray, js_os_detect
* etc

The PR is for the following redmine ticket:
http://dev.metasploit.com/redmine/issues/8500