Make shortening of FMU names optional in FMU generation

[casella]

In order to fix #12916 (CMake failing on Windows because of too long pathnames), #13101 changed the default name of the FMU to a shorter hashed version.

This is currently necessary on Windows because the tools in MinGW that we are using are not fully compliant with long path names. However, it is causing unnecessary issues to users like @rfranke which build FMUs on Windows.

This may be resolved with more recent versions of MinGW, @adrpo should check that. If not, I would propose to add an extra input

input Boolean shortenFileNamePrefix = true|false "= true replaces the full class name with shortened hashed string, default = true on Windows, false on Linux"

Temporary directories can be kept with hashed names as we did in #11554, as they have no use for the end user.

Keeping @rfranke in the loop.