[C++] Add FileSystem::MakeUri() to serialize file locations to URIs

[asfimport]

Making the transform FS -> URI bijective would greatly simplify unambiguous location of files and serialization of filesystems. Something like:

Result<std::string> FileSystem::MakeUri(std::string path = "/");

Difficulties:

• SubTreeFileSystem::MakeUri("/") would probably return a URI referring to its base directory in the wrapped filesystem, which wouldn't roundtrip to a SubTreeFileSystem with FileSystemFromUri
• Not all of s3's parameters are supported in a URI

Reporter: Ben Kietzman / @bkietz

_{Note: This issue was originally created as ARROW-10222. Please see the migration documentation for further details.}

[asfimport]

Todd Farmer / @toddfarmer:
This issue was last updated over 90 days ago, which may be an indication it is no longer being actively worked. To better reflect the current state, the issue is being unassigned. Please feel free to re-take assignment of the issue if it is being actively worked, or if you plan to start that work soon.

[github-actions]

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