Moved remaining content into relevant places.
Added `load_design.rst` to more scripting.
Split fsm handling and abc out of optimization passes. Also moved things around to match the general flow previously described.
Changed generic `synth` for `prep` instead.
Replace `typical_phases.rst` and `examples.rst` with a single `example_synth.rst`.
Also updating the counter example to match.
Aims to reduce redundancy, and simplify the getting started section.
Details on things like `proc`, `memory` and `fsm` should instead be in the advanced section (under the new `synth` subsection).
Mostly in the `more_scripting` section, with part of the intro in the `scripting_intro`.
Also includes an extra todo on the installation page and some extra notes on where to find `show` details where relevant.
Krystine Sherwin