[Retro] Document the supported environments & platforms

[AltTesterBot]

We should have a documented list of the environments & platforms that we support.

Description

We often get the question about what platforms & environments we support.

To Do:

• document a list of the supported platforms & environments
  https://docs.google.com/spreadsheets/d/1V-qEX4hUrTwjKrtybW5JmuJZgH82SZKK_Kcpi6vAQ28/edit#gid=0
• the list should be also added in a document that the users could easily access when they need this information

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_{You can find the original issue from GitLab here.}