Simplify _Q_opt in parmest with block scenario structure.

[sscini]

Fixes # .

Summary/Motivation:

_Q_opt, the main model building and solving function within parmest, is still heavily dependent on MSISPPY, and the code is becoming outdated and difficult to interpret. The goal of this PR is to redesign _Q_opt to work without this dependence, retaining all the current functionality

Changes proposed in this PR:

-_Q_opt redesign, using a block structure, with minimal changes needed to functions that utilize it.

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[sscini]

@djlaky @adowling2 Here are my initial thoughts on the redesign. Please provide feedback on code layout to this point.

[sscini]

Dan and I had a good conversation today about the functional things needed in the redesign, and how to go about adding components to the overall block and sub-models. Working to implement changes, closely related to what is done currently in doe's _generate_scenario_blocks.

[adowling2]

Nice progress