Allow using Deno as package manager

### Command

new

### Description

Add `deno` as a package manager, such that it can be used during project creation or automatically used when it's lockfile is found.

```sh
ng new --package-manager=deno my-project
```

### Deno Details

- Add package command: [`deno add`](https://docs.deno.com/runtime/reference/cli/add/)
- Install all command: [`deno install`](https://docs.deno.com/runtime/reference/cli/install/)
- Lockfile file: `deno.lock`
- Dev only flag: [`--dev`](https://docs.deno.com/runtime/reference/cli/add/#options-dev) (e.g. `deno add --dev `)

Deno seems to have the same commands as the other package manager options, and is similar to `pnpm` in that it installs packages with symlinks in `node_modules`.

### Describe the solution you'd like

Deno works similar to `bun` as package manager.

### Describe alternatives you've considered

None. If `bun` is supported, it seems reasonable to support `deno` too.

Start with the `new` command's existing package-manager handling and compare the `bun` path with the requested Deno commands. Done means `ng new --package-manager=deno my-project` works, `deno.lock` triggers automatic selection, and package additions use `deno add` with `--dev` when appropriate.

Written by the indexing model from the issue text.