[RFC] enhance topology validation

[fredoh9]

Describe the bug
Lately I have worked on topology clean up and enhancements. Before every push I need to make sure no side effect nor unwanted changes are accidentally introduced. Simple changes also required careful check. Sometime quotation or extra , create different results. hard to find.

Current sof-ci supports checkpatch and build. Defintely we need more.

1. M4 macro validation. I found a feature request, [FEATURE] Improve topology macro argument validation #2515. I'm looking at how this might be implemented and integrated.
2. Graph comparison, this is low hanging fruit. We have a tool to generate dot and png. I can compare dot text files and throw an error if diff is found. At least we can keep same graph by this.
3. Ultimately we need diff *.conf files. I did manually every time and go through line by line. Every change will make some difference in conf file. Some are desired, some are not. I need some input/comment/suggestion for this task.

This is one example from I fixed(#2677) with sof-apl-dmic-a4ch-b2ch.conf comparison.

DMIC is accidentally put(or not removed). Hard to catch this error without comparing conf. May be 1. m4 macro validation task above might help here if we can validate type of parameter.

PIPELINE_PCM_ADD(sof/pipe-volume-capture.m4,
        6, 6, 4, s16le,
        1000, 0, 0, DMIC,
        48000, 48000, 48000)

[lgirdwood]

@fredoh9 some of these need to go into the ALSA compiler, i..e validation of type

[fredoh9]

There is no immediate and EASY automated solution.
Close for now.