Need a clear error message when Pkg.add fails

[hearnsj]

The verbose error message when Pkg.add cannot find a compatible version of a package is highly confusing. It is not at all clear to beginenrs what is happening here.
The error message should start by saying without ambiguity:
You are trying to install Package XYZ. I can find no version of this package which is compatible with the version of Julia which you are using or the currently installed packages.

For example:
https://discourse.julialang.org/t/pkg-add-error-unsatisfiable-requirements-how-to-understand-and-attack-these/16213/11

The current error messages plus lots of version numbers:
possible versions are:
restricted by compatibility requirements with LanguageServer:
restricted by julia compatibility requirements to versions:

Yes, these are needing for figuring out what the exact problem is. However the key phrase is at the end and is unparseable by me anyway:
restricted by julia compatibility requirements to versions: 0.4.0-0.4.1 or uninstalled - no versions left

I now know this means 'Hey - this package only works in Julia 0.0.0 to 0.4.1'.
But the 'or uninstalled' is pretty meaningless.

[fredrikekre]

See #819

[hearnsj]

@fredrikekre Very much accepted