lldb should support debuginfod client protocol to fetch debuginfo / source code

[fche]

The llvm toolkit contains an elfutils debuginfod reimplementation for various purposes, but lacks what is perhaps its most compelling use: lldb. Other debuggers use this technology to fetch debuginfo & source code automatically, but lldb lacks this function.

https://reviews.llvm.org/D75750 was an early draft of this effort, but it's been apprx. abandoned.

[llvmbot]

@llvm/issue-subscribers-lldb

[russelltg]

Duplicate of #52732