migrate "tool discrimination" content and relink references

[weblorin]

We have many pages that link to riverscapes.net/tools/discrimination
this content is no longer public, but is in https://github.com/Riverscapes/riverscapes-website-jekyll/blob/135e50933bc4777a124fddb042ecacfbe1163468/Tools/discrimination.md

Migrate this to refactored documentation site and relink pages.