feat: Provide the option to use InstantSeal/ManualSeal for consensus

[aaronbassett]

It would be useful to be able to reduce the time taken for consensus/block authoring during development. Perhaps devs could switch consensus algorithms via a pop build parachain flag?

[AlexD10S]

Thanks @aaronbassett for the feedback. This feature is not in our short-term roadmap, but we have considered the possibility of customizing consensus algorithms in your parachain. We'll definitely look into it.