Auto include native files based on the detected target

[MangelMaxime]

To avoid having to write:

<ItemGroup>
    <!-- Your F# code is already included because of the previous rules, so you only need to ensure the .js files are included as well -->
    <Content Include="**/*.js" Exclude="**\*.fs.js" PackagePath="fable/%(RelativeDir)%(Filename)%(Extension)" />
</ItemGroup>

we could auto include this rules based on the PackageTags.

For example, if fable-javascript is set then we can add the rules from the snippet above.

Same goes on for python, rust, etc.