rewrite uri logic to always perform normalization

[Techatrix]

We cannot assume that client and server will use the exact same uri string to refer the same file. To remedy this, we will now always run some normalization rules before using a uri. Previously we would sometimes use client uri strings as is and sometimes normalize them. fixes #2465

I've also made sure that UNC paths on windows are properly handled. Still depends on ziglang/zig#25681 to fix import lookups.