fix(cli/tools/installer): allow remote import maps

[satyarohith]

The previous version fetched the source of the specified local import map and recreated a new import map alongside the bin script.
This commit removes the old behavior and directly passes the specified import map URL to deno run without creating a new one.
This will enable us to support remote import maps for deno install.

Closes #10482

[kt3k]

I think this doesn't work for the local import map files. For example,

./target/debug/deno install -f --import-map=./import_map.json https://deno.land/std/examples/welcome.ts

This command creates the following installed shell script:

#!/bin/sh
# generated by deno install
exec deno run --import-map ./import_map.json 'https://deno.land/std/examples/welcome.ts' "$@"

So this installed script use different import map dependeng on the current directory.

I think we should change the behavior depending on the given import map path. And we also need test cases for this change.

[satyarohith]

I made it similar to how scripts are installed. It will now have an absolute file URL for relative paths. And I also added a test.

[kt3k]

@satyarohith Thank you for updating and adding tests! LGTM

[kt3k]

👍