* logging: Initial implementation
* logging: More encoder formats, better defaults
* logging: Fix repetition bug with FilterEncoder; add more presets
* logging: DiscardWriter; delete or no-op logs that discard their output
* logging: Add http.handlers.log module; enhance Replacer methods
The Replacer interface has new methods to customize how to handle empty
or unrecognized placeholders. Closes#2815.
* logging: Overhaul HTTP logging, fix bugs, improve filtering, etc.
* logging: General cleanup, begin transitioning to using new loggers
* Fixes after merge conflict
Use piles from which to draw config values.
Module values can return their name, so now we can do two-way mapping
from value to name and name to value; whereas before we could only map
name to value. This was problematic with the Caddyfile adapter since
it receives values and needs to know the name to put in the config.
