Add command to delete saved wallet config

**Describe the enhancement**

The wallet config command stores the configuration information for a wallet in the `config.toml` file which is then reused on all subsequent wallet operations. However, there is no way to remove/delete a wallet configuration even when the wallet may no longer be needed.

Adding a command to delete a saved wallet configuration will help reduce the number of redundant wallet configurations and improve the amount of data saved in the config file.

**Use case**

- This will allow users to clean up the wallet config file and remove redundant wallet configs.

Start from the existing wallet config command and the config.toml handling it uses. Trace how saved wallet configurations are selected for later wallet operations, then define done as a command that removes the chosen configuration and prevents it from being reused.

Written by the indexing model from the issue text.