feat(unstable): support caching npm dependencies only as they're needed (#27300)

Currently deno eagerly caches all npm packages in the workspace's npm
resolution. So, for instance, running a file `foo.ts` that imports
`npm:chalk` will also install all dependencies listed in `package.json`
and all `npm` dependencies listed in the lockfile.

This PR refactors things to give more control over when and what npm
packages are automatically cached while building the module graph.

After this PR, by default the current behavior is unchanged _except_ for
`deno install --entrypoint`, which will only cache npm packages used by
the given entrypoint. For the other subcommands, this behavior can be
enabled with `--unstable-npm-lazy-caching`


Fixes #25782.

---------

Signed-off-by: Nathan Whitaker <17734409+nathanwhit@users.noreply.github.com>
Co-authored-by: Luca Casonato <hello@lcas.dev>

cli/module_loader.rs

@@ -156,6 +156,7 @@ impl ModuleLoadPreparer {
           graph_kind: graph.graph_kind(),
           roots: roots.to_vec(),
           loader: Some(&mut cache),
+          npm_caching: self.options.default_npm_caching_strategy(),
         },
       )
       .await?;