Add xiaomi_miio vacuum service to load map

[paoloantinori]

Breaking change

Proposed change

xiao_mii, added service for vacuum device to load maps.
See https://community.home-assistant.io/t/xiaomi-vacuum-restore-select-backup-map-multi-floor-support/282345

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[frenck]

According to the response on the forum; this should not work:

https://community.home-assistant.io/t/xiaomi-vacuum-restore-select-backup-map-multi-floor-support/282345/4

Also, listed in that same thread by you, that you were not able to test it?

[paoloantinori]

Yes, sorry, we can probably stash this for now. It seems that the base library providing the future is not really working, so despite being this PR functionally correct, it won't provide the desired behavior.