[feature request] infer index root by reading scip metadata

[ckipp01]

Currently using using src to upload a SCIP file it assumes that the root is the directory the actual directory the index is in. You can see this in:

src-cli/cmd/src/code_intel_upload_flags.go

Lines 320 to 325 in c0cad1a

	// inferIndexRoot returns the root directory based on the configured index file path.
	//
	// Note: This function must not be called before codeintelUploadFlagset.Parse.
	func inferIndexRoot() (string, error) {
	return codeintel.InferRoot(codeintelUploadFlags.file)
	}

There are situations where an integrations may spit this file out not in the root of the dir. Then when you upload you need to ensure you're setting -root or it may be inferred incorrectly.

As an alternative I'd be great if this could just be pulled form the project_root field of the metadata in the scip protocol. This would allow for an upload that is uploading a scip.index file not in the root to also not have to define the -root flag.