TS-2401: ProcessManager doesn't need a directory path
TS-2401: Remove unused global management_directory
TS-2401: Replace system_root_dir with Layout::prefix
TS-2401: Remove unused TS_BUILD_SYSCONFIGDIR
TS-2401: Remove global system_log_dir

In the 2 places that actually look at this, we implement the
predictable semantics of using proxy.config.log.logfile_dir (relative
to $PREFIX) if it is specified. Otherwise we use the compile-time
log directory.  In either case, we never fall back to different
directories. We either use the one specified by the operator or
fail loudly and suddenly.
TS-2401: Remove global system_runtime_dir

Introduce RecConfigReadRuntimeDir() to centralize overriding
Layout::runtimedir with proxy.config.local_state_dir. Use this to
replace all the instances of system_runtime_dir.
TS-2401: Remove system_config_directory

Remove all the places the global system_config_directory is used,
replacing it with Layout::get()->sysconfdir where appropriate.
TS-2401: Remove cache_system_config_directory

Remove the global cache_system_config_directory array. It was only
really being used for an error message. The only real place where
it could have been use already used Layout::sysconfdir.
TS-2401: Add RecConfigReadLogDir() to wrap proxy.config.log.logfile_dir access
TS-2401: update records.config layout documentation
TS-2401: update CHANGES