The fix that was initially put forth in #2971 was good, but only for
up to one layer of nesting. The real problem was that we forgot to
increment nesting when already inside a block if we saw another open
curly brace that opens another block (dispenser.go L157-158).
The new 'handle' directive allows HTTP Caddyfiles to be designed more
like nginx location blocks if the user prefers. Inside a handle block,
directives are still ordered just like they are outside of them, but
handler blocks at a given level of nesting are mutually exclusive.
This work benefitted from some refactoring and cleanup.
This splits automatic HTTPS into two phases. The first provisions the
route matchers and uses them to build the domain set and configure
auto HTTP->HTTPS redirects. This happens before the rest of the
provisioning does.
The second phase takes place at the beginning of the app start. It
attaches pointers to the tls app to each server, and begins certificate
management for the domains that were found in the first phase.
