[SAoC2022] Replace libdparse with dmd-as-a-library in D-Scanner

[Lucian Danescu]

[SAoC2022] Replace libdparse with dmd-as-a-library in D-Scanner

Hello!

Since the last update I created PRs for the following visitors:
- 
[function_attributes](https://github.com/Dlang-UPB/D-scanner/pull/36)
- [alias_syntax](https://github.com/Dlang-UPB/D-scanner/pull/38)

Also finished the work on these PR's where mostly minor 
refactoring was needed:
- 
[imports_sortedness](https://github.com/Dlang-UPB/D-scanner/pull/35/)
- 
[final_attribute](https://github.com/Dlang-UPB/D-scanner/pull/34)
- [infinite_range](https://github.com/Dlang-UPB/D-scanner/pull/33)

I also found a small bug in the actual `D-Scanner`. It is 
supposed to throw a warning
in situations like this:
```
     private static:
         // ...
         private x;
```

Here my approach is to fix the warnings in `phobos`, so my 
version of `D-Scanner` wouldn't
fail when being applied to `phobos`. This is the 
[PR](https://github.com/dlang/phobos/pull/8620)
with the explanation.
There is a similar situation for other `D-Scanner` checks as 
well, but more updates on that the
next week when I will create PR's to fix the issues.

Also finished the work for the 
[PR](https://github.com/dlang/dmd/pull/14602) with the `location`
fix for `AliasDeclaration` that I also mentioned last week; and 
for the other
[PR](https://github.com/dlang/dmd/pull/14578) mentioned last 
week, adding `isXExpression` in
`ASTBase`

Thank you!