[19.0][IMP] base_tier_validation: rewrite the documentation

[bosd]

The readme of base_tier_validation was written for developers and had aged:

• It linked to purchase_tier_validation in purchase-workflow; it now points to this repository (without a version, so the link does not age) rather than listing every *_tier_validation module.
• The only known issue on the roadmap was fixed in 13.0.1.2.2.
• Nothing explained what tier validation exceptions are for, or in which order the reviews are done (highest sequence first, which surprises people).

This rewrites DESCRIPTION and CONFIGURE in functional terms and adds CONTEXT and USAGE. The developer notes are kept, shorter, at the end of the description.

Some open PRs add a few lines to CONFIGURE.md (#41, #46, #47, #83) or ROADMAP.md (#80); whichever merges second needs a small rebase, which I'll do.

[OCA-git-bot]

Hi @LoisRForgeFlow,
some modules you are maintaining are being modified, check this out!

[bosd]

@axelpriem Can you please review?

[axelpriem]

@axelpriem Can you please review?

You want me to review your code, even though I'm not a member of OCA?...

[bosd]

@axelpriem Yes, Well, this one is actually only about the documentation.
The reason I asked, is because I wanted to have a fresh pair of 👀 eyes on it :)

[axelpriem]

@axelpriem Yes, Well, this one is actually only about the documentation. The reason I asked, is because I wanted to have a fresh pair of 👀 eyes on it :)

I don't mind doing it, but I know very little about the module and the functionality in it. It was just failing my GIT pipelines in a project, that's why I asked for the change. So I'm not sure if my review of the readme files would be useful...