explain where docs are

keep netlify config for now (disabled in the app), but only make it ship the _redirects file
add rule for 'install.sh'
move _redirects file into docs/ directory
document redirects and Netlify

Signed-off-by: Daniel Holbach <daniel@weave.works>

netlify.toml

@@ -1,3 +1,3 @@
 [build]
-  command = "./copy-docs-assets.sh && mkdocs build && cp _redirects site/"
+  command = "mkdir -p site && cp docs/_redirects site/"
   publish = "site"