Add a redirects page primarily generated from the existing anchor
rewrite files. This page should eventually provide redirect support.
Migration was mostly automated using
https://github.com/philwebb/spring-boot-redirects-generator
See gh-40062
Update `anchor-rewrite.properties` to fix a few errors and remove
elements that no longer exist. This commit also fixes a few anchors
in some `.adoc` files.
See gh-40062