ChannelSettingsKt

This information can be encoded as a QRcode/url so that other users can configure
their radio to join the same channel.
A note about how channel names are shown to users: channelname-X
poundsymbol is a prefix used to indicate this is a channel name (idea from @professr).
Where X is a letter from A-Z (base 26) representing a hash of the PSK for this
channel - so that if the user changes anything about the channel (which does
force a new PSK) this letter will also change. Thus preventing user confusion if
two friends try to type in a channel name of "BobsChan" and then can't talk
because their PSKs will be different.
The PSK is hashed into this letter by "0x41 + [xor all bytes of the psk ] modulo 26"
This also allows the option of someday if people have the PSK off (zero), the
users COULD type in a channel name and be able to talk.
FIXME: Add description of multi-channel support and how primary vs secondary channels are used.
FIXME: explain how apps use channels for security.
explain how remote settings and remote gpio are managed as an example