Allow configuring phone number discoverability on register and/or verify commands

[orazioedoardo]

Matches new official Signal apps defaults.

[AsamK]

Both options can be set using the updateAccount command.

[orazioedoardo]

I know but this means that there is a time window where phone number can be shared and discovered by others that may have it saved in the address book.

[orazioedoardo]

Phone number discoverability seems saved in the Storage Service so I guess enabling it on a Android or iOS device and then registering signal-cli with the same number while providing the PIN would work right?

[AsamK]

yes, that should work.