[Enhancement] Allow metrics for other segment types, noise, flat

[RussellSB]

Allow noise & flat segments to have calculated SNR, total change, rel change,and change rank metrics in analyse segments file. So people can numerically quantify the shape behaviour in conjunction with our categorical tags. This was initially disabled, thinking that change rank should only be with respect to up/down. But since people can use filter segments its not strictly necessary. They can reason about it how they'd like.

[RussellSB]

Note documentation will need to be updated with respect to this new output also:

• README
• MKDocs Quickstart
• MKDocs Tutorials (would require rerunning, then running the .sh script for string fixes)

[RussellSB]

@gyr0tron

[RussellSB]

Here is the place to start! Where the main code changes would take place: https://russellsb.github.io/pytrendy/main/reference/pytrendy/post_processing/segments_analyse/

Things like cumulative total change (line 72) or change rank (line 89) should be fairly straight forward.
For relative percent change (lines 53-62) can change the logic do just work with the abs difference. I realise the current logic is a bit redundant for having diff versions of segment_enhanced['change'] = float(val_max - val_min) depending on whether Up or Down