Support URIs in import decl

[hinshun]

• (*codegen.CodeGen).EmitImport uses the same ParseModuleURI.

Example:

import go from "git://github.com/openllb/hlb@master:/go.hlb"

fs default() {
    go.lint src
}

fs src() {
    local "." with includePatterns("**/*.go", "go.mod", "go.sum", ".golangci.yml", ".git", "**/*.json")
}