Add recommendations on cybersecurity topics w.r.t. to FMU exchange

[chrbertsch]

The issue was raised how cybersecurity can be ensured w.r.t to FMU exchange.

E.g., how can we make sure that an FMU containing binaries is still the same as it was compiled by a supplier (and not manipulated by a third party)?

These topics are not covered by the FMI standard, but any kind of authentication mechanisms that can be used for the validation of digital artefacts cab be used for FMUs, e.g. secure hash values that are exchanged together with the FMU.

We should comment on this in the IG, and provide recommendations or links to other standards etc.

See also 4.3 of https://2017.international.conference.modelica.org/proceedings/html/submissions/ecp17132329_DurlingPalmkvistHenningsson.pdf