Dafny-to-Rust code generator

[MikaelMayer]

Here is a tracking of the issues that a fully working Dafny-to-Rust code generator will have to solve:

• Emit Rust code #601 - close when new arrays are merged
• Rust backend broken in master, not detected by CI #5200
• Rust backend always includes runtime code, doesn't emit it unless building the target program #5203 - close when the part of the branch that does not emit runtime is merged.
• Unstable test due to timeout when executing Rust back-end #5321
• Unstable CLI test git-issues/git-issue-697j.dfy, related to Rust backend #5537
• Integrate MIRI as part of the CI to ensure no memory leak in the DafnyRuntimeRust #5567
• Second assignment to const crashes the Rust compiler #5642
• Support for enumerating finite datatypes in Rust #5643
• Error transpiling set into Rust #5644
• Bad code generated in Rust for recursive function having a local variable with the same name as a parameter. #5647
• Dafny-to-Rust: SelectFn should produce a tree instead of a raw string #5664
• Support for Rust tests #5666
• Dafny fails with most languages when using UTF-16 escape sequences #5737
• Make the Rust compiler run on nightly once it passes all tests #5560 (when all is finished)
• Find a way for DafnyWrittenCodeGenerators to report unsupported features from the Dafny side #5714 (may be forced by the above anyway)
• Dafny-to-Rust code generation is not simplifying all paths #5755 (optional)