Support multi-span errors and warnings (#4892)

## Description

A new `Diagnostic` type is introduced for detail description of compile
errors and warnings. The change is backward compatible. The existing
`CompileWarning`s and `CompileError`s will continue render as they had
before.

The `Diagnostic` is formed out of a:
- _Level_: Error or Warning.
- _Code_: Unique error or warning code. Placeholder for future. Not used
at the moment.
- _Reason_: Short description of the diagnostic, not related to a
specific error/warning. Answers the question "Why is this an
error/warning?" E.g., Because - "Constants cannot be shadowed".
- _Issue_: Short description of the concrete case that the compiler has
found. E.g., "Variable "X" shadows imported constant with the same name"
- _Hints_: Detailed description of the diagnostic placed in the source
code.
- _Help_: Additional friendly information that helps understanding and
solving the issue, but which is not related to a place in code.

![07C Constant shadowing - Alias - After 02 -
Terminology](https://github.com/FuelLabs/sway/assets/4142833/50c639a1-43f5-4bc2-afa2-5717652f0172)

The `Diagnostic`s are defined imperatively in code right now, pretty
much the sam way we do `CompilWarning`s at the moment. Development of a
proc-macro that should make de definitions declarative is out of scope
of #21.

## Known Limitations

The `annotate-snippets` library has a bug and a missing functionality
for which I opened issues:

- Wrong display of line numbers when using folding of lines of code.
This issue is fixed but there is no patch release provided:
rust-lang/annotate-snippets-rs#52 (comment)
- No possibility to remove the "note:" prefix as shown on the image
above: rust-lang/annotate-snippets-rs#59

These two issues are not blocking. Proposal is to wait for the official
support in the library, or contribute or in the worst case make a
workaround in our code.

## Demo (Before and After)

### Errors
![07A Constant shadowing - Alias -
Before](https://github.com/FuelLabs/sway/assets/4142833/5d67c5e5-d456-4762-b7c7-6fcf7340d6b3)

![07C Constant shadowing - Alias - After
02](https://github.com/FuelLabs/sway/assets/4142833/02691b39-3d08-4776-ba93-5ffeca4546ed)

### Warnings
![06A NonScreamingSnakeCaseConstName -
Before](https://github.com/FuelLabs/sway/assets/4142833/c27279d4-0e6c-4d05-9b00-da7121bb60ad)

![06B NonScreamingSnakeCaseConstName -
After](https://github.com/FuelLabs/sway/assets/4142833/483044f3-f190-4506-9e9e-2d03d70cb3f2)

Closes #21

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [ ] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [ ] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.