Improve Modelio documentation style and dead link

Currently, the style of Modelio's docs is very different than the rest of the documentation and appears out of date.


Concretely:
1. hyperlinks are written out in full length and are not integrated in the text.
2. latest Modelio version is stated as 3.0.1, which is incorrect "Latest version: 4.0.1 (Last update on February 3rd, 2020)"
3. link to "community quick start guide" is dead
4. some information is outdated and can easily be found at their website, such as the latest version (can always be found on their website and is prone to change)

Asides from the dead link this is a matter of style, but it does send a bad impression for the docs to be outdated.
@pglvdm do you know who is the owner of the documentation? If so I can reach out and hear if they are willing to update the contents.

Start by locating the Modelio documentation section and comparing its link style with nearby documentation. Check the community quick start guide link and the current Modelio website, then update the outdated version reference, integrate full URLs into the surrounding text, and remove or revise information that changes frequently. Done means the links work and the section matches the documentation style.

Written by the indexing model from the issue text.