Flash firmware

[yoichiro]

Fix #662

This pull request has the following parts:

• FlashFirmwareDialog class. This provides a UI for users who want to flash a firmware on the catalog page.
• The Firmware writer service. This provides a feature to write a firmware to the MCU via a serial communication using Web Serial API.
• The management UI for keyboard owners to turn on/off the firmware flash feature for each uploaded firmware.