cmd, internal/build, docker: advertise commit date in unstable build versions (#19522)

* add-date-to unstable

* fields-insteadof-split

* internal/build: support building with missing git

* docker: add git history back to support commit date in version

* internal/build: use PR commits hashes for PR builds

cmd/geth/misccmd.go

@@ -112,6 +112,9 @@ func version(ctx *cli.Context) error {
 	if gitCommit != "" {
 		fmt.Println("Git Commit:", gitCommit)
 	}
+	if gitDate != "" {
+		fmt.Println("Git Commit Date:", gitDate)
+	}
 	fmt.Println("Architecture:", runtime.GOARCH)
 	fmt.Println("Protocol Versions:", eth.ProtocolVersions)
 	fmt.Println("Network Id:", eth.DefaultConfig.NetworkId)