FoD: rename `dast-scan` subcommands for legacy scanning

[kadraman]

With the upcoming implementation of FoD DAST Automated feature, it makes more sense to preserve the dast-scan subcommands that will be relevant to this, e.g. dast-scan start, dast-scan setup etc. Any existing DAST commands should be renamed with "-legacy" postfix and hidden. We are assuming there will be a different scan type for DAST Automated but this is not confirmed yet.

Renamed commands:

• dast-scan start to dast-scan start-legacy
• dast-scan get-config to dast-scan get-config-legacy

All other commands can stay the same as they as scan generic with overriden scan type.