Product license verification in Console (#518)

Operator UI - Provide and store License key
- New License section in Operator UI will allow user to provide the
  license key via input form
- New License section in Operator UI will allow the user to fetch the
  license key using subnet credentials
-  Console backend has to verify provided license is valid -
   https://godoc.org/github.com/minio/minio/pkg/licverifier#example-package
-  Console backend has to store the license key in k8s secrets

Operator UI - Set license to tenant during provisioning
- Check if license key exists in k8s secret during tenant creation
- If License is present attach the license-key jwt to the new console
tenant via an environment variable

Operator UI - Set license for an existing tenant
- Tenant view will display information about the current status of the
  Tenant License
- If Tenant doesn't have a License then Operator-UI will allow to attach
new license by clicking the Add License button
- Console backend will extract the license from the k8s secret and save
the license-key jwt in the tenant console environment variable and
redeploy

models/license.go

@@ -0,0 +1,75 @@
+// Code generated by go-swagger; DO NOT EDIT.
+
+// This file is part of MinIO Console Server
+// Copyright (c) 2020 MinIO, Inc.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+package models
+
+// This file was generated by the swagger tool.
+// Editing this file might prove futile when you re-run the swagger generate command
+
+import (
+	"github.com/go-openapi/strfmt"
+	"github.com/go-openapi/swag"
+)
+
+// License license
+//
+// swagger:model license
+type License struct {
+
+	// account id
+	AccountID int64 `json:"account_id,omitempty"`
+
+	// email
+	Email string `json:"email,omitempty"`
+
+	// expires at
+	ExpiresAt string `json:"expires_at,omitempty"`
+
+	// organization
+	Organization string `json:"organization,omitempty"`
+
+	// plan
+	Plan string `json:"plan,omitempty"`
+
+	// storage capacity
+	StorageCapacity int64 `json:"storage_capacity,omitempty"`
+}
+
+// Validate validates this license
+func (m *License) Validate(formats strfmt.Registry) error {
+	return nil
+}
+
+// MarshalBinary interface implementation
+func (m *License) MarshalBinary() ([]byte, error) {
+	if m == nil {
+		return nil, nil
+	}
+	return swag.WriteJSON(m)
+}
+
+// UnmarshalBinary interface implementation
+func (m *License) UnmarshalBinary(b []byte) error {
+	var res License
+	if err := swag.ReadJSON(b, &res); err != nil {
+		return err
+	}
+	*m = res
+	return nil
+}