Multiple filter options

It would be very handy if you could specify several parameters at once for the filter query, e.g. something like

`https://packagist.org/explore/?type=contao-bundle~contao-module`

instead of

https://packagist.org/explore/?type=contao-bundle and
https://packagist.org/explore/?type=contao-module

Start from the /explore/ filter query handling described in the issue and inspect how the current type parameter is parsed. Determine how multiple type values should be represented and combined, then verify that the explore results include packages matching each requested type while preserving existing single-type behavior.

Written by the indexing model from the issue text.