…lib-cleanup

Hopefully fixes dafny-lang#4838

### Description
<!-- Is this a user-visible change? Remember to update RELEASE_NOTES.md
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<!-- Is this a bug fix for an issue visible in the latest release?
Mention this in the PR details and ensure a patch release is considered
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### How has this been tested?
<!-- Tests can be added to
`Source/IntegrationTests/TestFiles/LitTests/LitTest/` or to
`Source/*.Test/…` and run with `dotnet test` -->

<small>By submitting this pull request, I confirm that my contribution
is made under the terms of the [MIT
license](https://github.com/dafny-lang/dafny/blob/master/LICENSE.txt).</small>

Co-authored-by: Robin Salkeld <[email protected]>
Co-authored-by: Remy Willems <[email protected]>

…nstruction (dafny-lang#4850)

Co-authored-by: Fabio Madge <[email protected]>

### Description
- For Dafny content that is embedded in the Dafny CLI, such as the
standard library, expose their URIs using the `dafny:` scheme. This can
be used by the LSP client to implement custom behavior for opening these
files.

### How has this been tested?
- Added the test StandardLibraryTest.GotoDefinition

<small>By submitting this pull request, I confirm that my contribution
is made under the terms of the [MIT
license](https://github.com/dafny-lang/dafny/blob/master/LICENSE.txt).</small>

…lib-cleanup

# Conflicts:
#	Source/DafnyStandardLibraries/README.md
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries-arithmetic.doo
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries-cs.doo
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries-go.doo
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries-java.doo
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries-js.doo
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries-notarget.doo
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries-py.doo
#	Source/DafnyStandardLibraries/binaries/DafnyStandardLibraries.doo