Update Multi-Markets Integration content

[deboragracio]

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Description

Updates made to the Multi-Markets Integration page.
More details at: https://github.com/fiskaltrust/engineering/issues/1119

[deboragracio]

@LGuichet Hi Louis, I made some changes and improved the text on the Multi-Markets Integration page. Please review and let me know if they look accurate.

Also, I have some other questions:

1. Does the diagram image look correct?
2. Under Mapping Table, should we keep AT, DE, and FR markets only or does it stay as is? If so, can you confirm whether its values for those business cases are correct?

Thank you!

[StefanKert]

Let's just remove this file cause it is confusing to customers. v2 Allows multi market integration per default, so we don't need to do that.

[github-actions]

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