Replaces https://github.com/JuliaLang/julia/pull/53216 (I can't push to
that repo branch)

Adds
- making pkgimages for REPLExt
- Fixes PkgCompletionProvider location

Stdlib: Pkg
URL: https://github.com/JuliaLang/Pkg.jl.git
Stdlib branch: master
Julia branch: master
Old commit: f3b81f1aa
New commit: 6dd0e7c9e
Julia version: 1.11.0-DEV
Pkg version: 1.11.0
Bump invoked by: @IanButterworth
Powered by:
[BumpStdlibs.jl](https://github.com/JuliaLang/BumpStdlibs.jl)

Diff:
https://github.com/JuliaLang/Pkg.jl/compare/f3b81f1aac77acf08f5d847ead29ad0a228dec67...6dd0e7c9e99d578aa5477e2c78c91a161ce4c357

```
$ git log --oneline f3b81f1aa..6dd0e7c9e
6dd0e7c9e Revert "add test for recurring precompile" (#3779)
dbf114fa9 Merge pull request #3777 from JuliaLang/kc/repl_extension
a49d47981 fixup
e3edf3917 avoid prompting for git creds on CI (#3778)
510454343 make the `REPL` specific code into an extension
12d2de14e make `pkgstr` independent of REPL
```

---------

Co-authored-by: Dilum Aluthge <dilum@aluthge.com>
Co-authored-by: Valentin Churavy <vchuravy@users.noreply.github.com>
Co-authored-by: Kristoffer Carlsson <kcarlsson89@gmail.com>
Co-authored-by: Jameson Nash <vtjnash@gmail.com>