Add feature to scope select subscriptions prompt by tenant

[alexweininger]

This adds the ability to scope the select subscriptions prompt by tenant. It also adds the option to filter by account, but that's not implemented in this PR.

If a prompt is scoped to a tenant, it won't change any selected subscriptions that aren't in that tenant. Only subscriptions shown in the picker will be removed or added to the selected subscriptions setting.

[alexweininger]

A further improvement to the select subscription picker would be to group the picks by tenant/account

[alexweininger]

A further improvement to the select subscription picker would be to group the picks by tenant/account

Foiled by this

[nturinski]

This error is being thrown by us. I think there's no actual limitation with VS Code's quick picker that prevents us from doing it. As far as I know, the grouping is just us sorting everything by group and using the QuickPickItemKind.Separator in between each group.

[alexweininger]

This error is being thrown by us. I think there's no actual limitation with VS Code's quick picker that prevents us from doing it. As far as I know, the grouping is just us sorting everything by group and using the QuickPickItemKind.Separator in between each group.

Yeah I was tempted to @ you fix it