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).
see also previous commit
Also updates `scripting_intro.rst` to use literal includes, and uses individual image outputs to avoid the intermediary `.tex` file to join them all.
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.
