Features and Templates UX with growing collections

## Context

Once we opened up the dev container spec, we moved to a model of community-hosted Templates and Features (through "Collections"), rather than a mono-repo where the spec maintainers own everything.

We've seen tremendous and fast-paced growth in our [collections](https://containers.dev/collections), which is very exciting! Though this growth poses an interesting challenge: how do we effectively display these collections in supporting tools without the list getting too long?

## Current examples

Supporting tools like VS Code and GitHub Codespaces surface the Templates and Features from the spec's [index](https://github.com/devcontainers/devcontainers.github.io/blob/gh-pages/_data/collection-index.yml). While currently effective overall, it'll pose more challenges over time:

- Uncertainty over which Template or Feature to choose - it can be confusing or overwhelming trying to consider what each one does, where it comes from (publisher), etc
- Latency in loading and searching through so many artifacts
- Process of browsing and getting more info is disruptive
- Brings user to github.com, rather than staying in their editor

## Potential solutions

- Sort by verified Templates or Features first
- Need ability for checkmark for collections beyond those hosted in the [devcontainers GitHub org](https://github.com/devcontainers)
- Filtering to a more manageable and applicable list
- i.e. filter by OS, tech stack
- In-product marketplace for getting more info (to avoid being redirected out to GitHub)

## Next steps

Share this issue with the community, including in our dev container community [Slack channel](https://github.com/devcontainers/community/discussions/3), to get broader feedback.