Add the "Syften Keyword Alerts" guide to the Wiki

[zackkrida]

Testing instructions

1. Install requirements pip3 install -r requirements.txt
2. Run the wiki locally mkdocs serve -a localhost:9000
3. Review http://localhost:9000/community/ and click on the Syften guide
4. Review the Syften guide (at http://localhost:9000/community/guides/syften-keyword-alerts/)

The guide has already been reviewed for the process itself and spelling. Feel free to make suggestions but the focus should be on the wiki integration.

[kgodey]

I only took a very brief look.