Revamp sncast cli

[cptartur]

As part of this issue, let's design and implement changes to sncast cli.

• Remove global arguments that are not in fact global (e.g. --account can always be passed but is not handled by sncast account methods)
• Consider improving the validation of optional arguments (i.e. some of them are mutually exclusive or should be provided at the same time, it is likely this can be resolved on clap level)

This should be implemented in a non-breaking manner: changes should be proposed through design-doc, then we should deprecate anything that can be deprecated and in future versions we should introduce our changes. This will likely result in some conflicting arguments initially, but it less likely to break users' scripts etc.

After release that introduce warnings:

• Restore tests to the previous version, they are marked as TODO(#2552)

[cptartur]

Closing in favor of #2603