Migrate the documentation presentation to MkDocs

[Tzaphkiel]

Decision has been taken to migrate the documentation to readthedocs.org.

We should take this opportunity to consolidate and improve the current documentation.
This repository will details the CSV format part of the full documentation glued together in sdmx-im.

[pedroacarranza]

@dosse @agent96 Is this covered by the work being done by HMS?

[dosse]

Yes, this was supposed to achieve the same objective: easy management of the technical standards inside GitHub using md pages and a tool to publish them as a nicely readable web site.

[Tzaphkiel]

So, should this issue not be closed?

[dosse]

So, should this issue not be closed?

No, let's continue to use it for the currently ongoing migration using MkDocs. I changed the title accordingly. --> @jr-hms