Allow configuring/reordering the band display

[grimsteel]

First, I wanted to let you know how helpful this library has been to me! The work you (and the many other people involved in this Mi Band community) have done is really amazing.

This allows configuring what items show on the band display

Usage:

from constants import DISPLAY_ITEMS

band.setBandDisplay(DISPLAY_ITEMS.ALL_ITEMS) # Show every item except MI Home
band.setBandDisplay([DISPLAY_ITEMS.WORKOUT, DISPLAY_ITEMS.STATUS, DISPLAY_ITEMS.MORE, DISPLAY_ITEMS.HEART_RATE]) # Display those items in that order

miband4/constants.py

Lines 108 to 114 in 97e1367

	STATUS = 0x01
	HEART_RATE = 0x02
	WORKOUT = 0x03
	WEATHER = 0x04
	MI_HOME = 0x05 # I have no clue what this does. Pressing it does nothing for me
	NOTIFICATIONS = 0x06
	MORE = 0x07 # While the app doesn't allow you to remove this, I tried and it works perfectly

When I was looking at the BT Packets, I noticed that the app was always skipping over the display item with ID 5. When I tried making that display item visible, I got something called "Mi Home". Maybe that's a HA thing they have that's not there by default.

I'm working on adding weather support!