[Documentation] Check and complete the documentation on the installation of Mia

[servoz]

We have to carefully test, check and complete if necessary the documentation for the installation of Mia for user. We propose now the installation of Mia in "light" version, without viewer, or in virtualized version, using images of BrainVISA.

It is thus necessary to test for the 3 OS (linux, macos, windows) and for the two types of installation ("light" or "with virtualization").

In most cases, it will only be a matter of checking that the documentation is really functional and sufficiently detailed for an ordinary user without any particular computer knowledge. On the other hand, there is clearly the macos / "with virtualization" part to write