* config: add customization options for logging
* config: validate log fields
* proxy: add support for logging http request headers
* log subset of headers
* add support for logging the http query
* fix test name
* use strings.Cut, add unit tests
* config: add customization options for logging
* config: validate log fields
* proxy: add support for logging http request headers
* log subset of headers
* fix test name
* dont use log.HTTPHeaders for access logs
* canonicalize http/2 headers