This commit adds CJS and ESM Node resolvers to the "--compat" mode.
The functionality is spread across "cli/compat" module and Node compatibility
layer in "deno_std/node"; this stems from the fact that ES module resolution
can only be implemented in Rust as it needs to directly integrated with
"deno_core"; however "deno_std/node" already provided CJS module resolution.
Currently this resolution is only active when running a files using
"deno run --compat --unstable <filename>", and is not available in other
subcommands, which will be changed in follow up commits.
This commit adds automatic injection of Node globals when "--compat" flag
is present.
This is done by executing "https://deno.land/std/node/global.ts" as a "side module",
before main module is executed.
This commit makes "--compat" required to be used with "--unstable" flag, as some
of Node globals require unstable Deno APIs.
