Move configuration of Lassie from startup to a per fetch basis.

[kylehuntsman]

We can currently have configuration for a Lassie instance that is used on startup, but we have slowly added features that allow that same configuration on a per fetch basis. Documentation around this might be confusing or not very straightforward for a user trying to use Lassie. We have started to favor per fetch configuration. We should move the configuration from the initialization of a Lassie instance to the fetch call.

[hannahhoward]

@kylehuntsman One clarifying thing here: what we want to deal with is situations where the configuration is in both places, and in those situations, remove the "on construction" configuration.

Of the top of my head, some parameters that I'm aware of being doubled are:

• peer selection
• protocol selection
• max blocks
• possibly others

The ticket starts with an audit to figure out what duplicates exists, and then figuring out how to remove the on startup options.

[hannahhoward]

also one clarifying piece: when we say "on startup" we really mean on construction of a Lassie instance. For the fetch command, we only make one request, but we should still convert the CLI parameters to request parameters. For the daemon, parameters that can be configured on requests generally shouldn't be available as CLI options -- i.e. for daemon, I don't get to say I want fixed peers, unless I do it as an parameter when making an HTTP request.