Dead link on Project configuration page

[twinkarma]

Dead link found in the Annotation configuration section in the Project configuration page, it links to

https://gatenlp.github.io/gate-teamware/userguide/projectconfig.html

whereas the page is actually located at:

https://gatenlp.github.io/gate-teamware/userguide/project_config.html

[twinkarma]

Fixed in #207, the particular page is now located at https://gatenlp.github.io/gate-teamware/development/manageradminguide/project_config.html