#6935 Updated documentation for requirements

[offtherailz]

Description

This PR updates the requirements documentation, adding max versions and some notes about the reason of the max version indicated. So it's easier to maintain this document solving the linked issues, and simplify the things.

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: https:/geosolutions-it/MapStore2/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x", remove the others)

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe: Documentation

Issue

What is the current behavior?

#6935

What is the new behavior?

Breaking change

Does this PR introduce a breaking change? (check one with "x", remove the other)

• Yes, and I documented them in migration notes
• No

Other useful information

[offtherailz]

@mbarto do you know some differences in versions for stable version?

[tdipisa]

@offtherailz please backport this to 2021.02.xx