Multi-device bootloader updates

[davidcoulson]

Describe the enhancement

Updating the bootloader via the builder dashboard is only available per-device when selecting from the install page. Would be great if this was something that could be done through the multiple device selection.

Use cases

When updating bootloader on multiple devices it's easier just to use esphome CLI than the builder. Multi device build works great, so follow same example.

Visual examples

No response

Anything else?

Yes, i realize bad things can happen when updating the bootloader. Maybe bury it under advanced options somewhere to avoid someone accidentally picking it and having to flash their device over serial/USB.