fix: make LibVersionSwitcher links with '/platform' filter

[5d]

Issue #, if available:

Description of changes:

• Fix the generated links in LibVersionSwitcher with platform filter.

  • Links with /lib is with kind platform in the URL.

• Use dynamic route path in FilterSelect component

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[5d]

Might be better to have version info as a parameter inside the query. Something like lib/project-setup/prereq/q/platform/[platform]/version/[version]. We can redirect to latest version when a version for a platform doesn't exist. Not sure whether this is possible in Nextjs.