Add format codes for local FQDN

[yadij]

No description provided.

[rousskov]

Here and elsewhere in this PR, please avoid the term "local FQDN". It is confusing (e.g., was some special a "local" DNS resolver used to obtain that FQDN?) and not descriptive enough ("address of the last server or peer connection" matches two different addresses, not one).

I do not insist on any specific wording, but something like this would address the problem:

Suggested change

	<lA Local FQDN for address of the last server or peer connection
	<lA FQDN for the local (a.k.a. source) address of the last Squid-to-server (including Squid-to-cache_peer) TCP connection

N.B. LFT_CLIENT_LOCAL_FQDN and LFT_SERVER_LOCAL_FQDN do not need to be renamed. In that existing naming pattern, "local" binds to "from-client" and "to-server" connection rather than binding to "FQDN".

[rousskov]

Please mimic existing Dns::ResolveClientAddressesAsap logic to enable "early" or "as soon as possible" DNS lookups of these addresses.

I suggest naming the new flag ResolveClientLocalAddressesAsap and renaming the old flag to ResolveClientRemoteAddressesAsap. Using ResolveLocalClientAddressesAsap and ResolveRemoteClientAddressesAsap is also OK but does not match our LFT_CLIENT_LOCAL_FQDN naming pattern.

Same for tcpServer->local lookups, of course -- Dns::ResolveServerLocalAddressesAsap.

[rousskov]

Please document (in cf.dada.pre) that these FQDNs are provided on a best-effort basis (i.e. that, when the corresponding DNS lookups are needed, Squid does not wait for them to complete when logging transactions).