As part of #151, indicated in !75, we need to introduce a new query for
package advisories that match various criteria.

We can add this query separately as a means to simplify the
implementation.

We can take advantage of the `sqlc.arg` directive to enforce the naming
of the struct, otherwise we end up with:

    type RetrievePackageAdvisoriesLikeParams struct {
	   Platform       string
	   Organisation   string
	   Repo           string
	   Owner          string
	   Platform_2     string
	   Organisation_2 string
	   Repo_2         string
	   Owner_2        string
	   Platform_3     string
	   Organisation_3 string
	   Repo_3         string
	   Owner_3        string
    }

This does unfortunately mean that we can't as easily copy-paste the
query, but hopefully it's trivial to tweak it.

This requires we create a constructor for the
`RetrievePackageAdvisoriesLikeParams` method to correctly, as we're
unable to use a `case` statement due to [0].

We also need to make sure we target out `owner` lookups better with
a rather large `where` statement, as otherwise we can't correctly filter
by the `owner`.

[0]: https://github.com/sqlc-dev/sqlc/issues/2736