node list and module list answer --json, and the nodes and modules verbs use it (hq ADR 0195)

The console's discovery reads the machines and the modules; parsing a printed column breaks when it
is reworded. Both now answer JSON on --json, as status and seats do, and the seat verbs ask for it.

cmd/mesh-controller/modules.go

@@ -147,6 +147,36 @@ func moduleCommand(ctx context.Context, args []string) error {
 		if err != nil {
 			return err
 		}
+		// **The same list, for something other than a person** (novox/hq ADR 0195): what each module
+		// is, where it runs, whether it is current, and what it says of itself.
+		if len(args) > 1 && args[1] == "--json" {
+			type listed struct {
+				Module       string   `json:"module"`
+				Version      string   `json:"version"`
+				Built        string   `json:"built,omitempty"`
+				Head         string   `json:"head,omitempty"`
+				Current      bool     `json:"current"`
+				Provided     bool     `json:"provided,omitempty"`
+				On           []string `json:"on"`
+				Provides     []string `json:"provides,omitempty"`
+				Requires     []string `json:"requires,omitempty"`
+				Claims       []string `json:"claims,omitempty"`
+				Capabilities []string `json:"capabilities,omitempty"`
+			}
+			out := make([]listed, 0, len(entries))
+			for _, e := range entries {
+				m := e.Manifest
+				l := listed{Module: m.Module, Version: m.Version, Built: e.Source.BuiltFrom, Head: e.Source.Head,
+					Current: e.Provided || e.Source.Repository == "" || e.Source.Current(), Provided: e.Provided,
+					On: append([]string{}, e.On...), Provides: m.Offers(), Requires: m.Requires,
+					Capabilities: m.Capabilities}
+				for _, c := range m.Claims {
+					l.Claims = append(l.Claims, c.At()+"/"+c.Name)
+				}
+				out = append(out, l)
+			}
+			return printJSON(out)
+		}
 		if len(entries) == 0 {
 			fmt.Println("this mesh knows about no modules yet")
 			return nil