Lifetime Mode is Confusing

[janinefreeman]

We'd like to make the "lifetime" option consistent across all technologies and potentially move it into the technology model rather than financial model, because it seems like a technology parameter to users. Or possibly it should be its own independent simulation variable somehow.

[brtietz]

system_use_lifetime_output is already in some of the technology models - do we need to generalize it further?

I'm not proposing this goes into 2021 release, just looking to close stuff we already finished.