Install with `tools` (only allowlisted tools, with versions from `.tool-versions`)

What do we think about the idea of adding support for something like this:

```yaml
[...]
steps:
- uses: action/checkout@v4
- uses: asdf-vm/actions/install@v2
with:
tools: |
action-validator
```
...so if you have a `.tool-versions` file like this:
```bash
$ cat .tool-versions
action-validator 0.5.3
gcloud 1.2.3
```
...then it would only `asdf install action-validator 0.5.3` (and not `gcloud`).

My hope is that this could simplify/speed up many jobs where you only need one particular tool for the thing you want to run.

Start by reading the behavior of asdf-vm/actions/install@v2 and how the action handles the .tool-versions file. Verify that the requested tools are selected, their versions come from .tool-versions, and unlisted tools are not installed; run the repository's existing action tests if available.

Written by the indexing model from the issue text.