Add JIRA starter links

src/github.com/matrix-org/go-neb/realms/jira/jira.go

@@ -33,6 +33,7 @@ type JIRARealm struct {
 	PublicKeyPEM   string // clobbered based on PrivateKeyPEM
 	PrivateKeyPEM  string
 	HasWebhook     bool // clobbered based on NEB
+	StarterLink    string
 }
 
 // JIRASession represents a single authentication session between a user and a JIRA endpoint.

src/github.com/matrix-org/go-neb/services/jira/jira.go

@@ -118,8 +118,13 @@ func (s *jiraService) cmdJiraCreate(roomID, userID string, args []string) (inter
 	cli, err := r.JIRAClient(userID, false)
 	if err != nil {
 		if err == sql.ErrNoRows { // no client found
-			return &matrix.TextMessage{"m.notice",
-				userID + " : You have not linked your JIRA account."}, nil
+			return matrix.StarterLinkMessage{
+				Body: fmt.Sprintf(
+					"You need to OAuth with JIRA on %s before you can create issues.",
+					r.JIRAEndpoint,
+				),
+				Link: r.StarterLink,
+			}, nil
 		}
 		return nil, err
 	}