cmd, dashboard, log: log collection and exploration (#17097)

* cmd, dashboard, internal, log, node: logging feature

* cmd, dashboard, internal, log: requested changes

* dashboard, vendor: gofmt, govendor, use vendored file watcher

* dashboard, log: gofmt -s -w, goimports

* dashboard, log: gosimple

dashboard/assets/types/content.jsx

@@ -18,24 +18,24 @@
 
 export type Content = {
 	general: General,
-	home: Home,
-	chain: Chain,
-	txpool: TxPool,
+	home:    Home,
+	chain:   Chain,
+	txpool:  TxPool,
 	network: Network,
-	system: System,
-	logs: Logs,
+	system:  System,
+	logs:    Logs,
 };
 
 export type ChartEntries = Array<ChartEntry>;
 
 export type ChartEntry = {
-	time: Date,
+	time:  Date,
 	value: number,
 };
 
 export type General = {
-    version: ?string,
-    commit: ?string,
+	version: ?string,
+	commit:  ?string,
 };
 
 export type Home = {
@@ -55,16 +55,42 @@ export type Network = {
 };
 
 export type System = {
-    activeMemory: ChartEntries,
-    virtualMemory: ChartEntries,
-    networkIngress: ChartEntries,
-    networkEgress: ChartEntries,
-    processCPU: ChartEntries,
-    systemCPU: ChartEntries,
-    diskRead: ChartEntries,
-    diskWrite: ChartEntries,
+	activeMemory:   ChartEntries,
+	virtualMemory:  ChartEntries,
+	networkIngress: ChartEntries,
+	networkEgress:  ChartEntries,
+	processCPU:     ChartEntries,
+	systemCPU:      ChartEntries,
+	diskRead:       ChartEntries,
+	diskWrite:      ChartEntries,
+};
+
+export type Record = {
+	t:   string,
+	lvl: Object,
+	msg: string,
+	ctx: Array<string>
+};
+
+export type Chunk = {
+	content: string,
+	name:    string,
 };
 
 export type Logs = {
-	log: Array<string>,
+	chunks:        Array<Chunk>,
+	endTop:        boolean,
+	endBottom:     boolean,
+	topChanged:    number,
+	bottomChanged: number,
+};
+
+export type LogsMessage = {
+	source: ?LogFile,
+	chunk:  Array<Record>,
+};
+
+export type LogFile = {
+	name: string,
+	last: string,
 };