Generate nginx 301 redirects for renamed files

[adam-cowley]

Currently when I rename a page, I add a :page-aliases: attribute, manually write the nginx rewrite rules and raise a PR on the neo4j.com.

It would be great if we could automatically raise a PR with the renamed/redirected files that have changed since the last build.

For example, moving /modules/ROOT/pages/cypher-basics-i.adoc to modules/cypher/pages/beginner.adoc would need the following added to src/nginx/includes/neo4j.com.redirects in the neo4j.com repo:

rewrite ^/developer/cypher-basics-i/$ /developer/cypher/beginner/ permanent;