Remove old (v1) reverse swap methods, models, bindings

[ok300]

When the new reverse swap methods were introduced, the existing v1 ones were deprecated but still supported.

Eventually we will want to remove the v1 methods and associated bindings, models:

• max_reverse_swap_amount
• fetch_reverse_swap_fees
• send_onchain
• in_progress_reverse_swaps

In the CLI, this means

• remove the [swap-out] group of commands
• rename the [swap-out-v2] command description prefix to [swap-out]