use snapshot.debian.org API to search and fetch debian source packages

Some debian package versions may be removed from debian repositories over time (eg. alsa-lib_1.2.3, found by the debian matcher for OHOS debian release on Apr 12, 2021, as of May 3, 2021 cannot be found any more in debian repos). This may lead to inconsistent and non-reproducible results by the debian matcher.

We should use snapshot.debian.org API instead (https://salsa.debian.org/snapshot-team/snapshot/raw/master/API), which would enable us to find more possibly matching versions in debian (and possibly closer matches), and would lead to stable and reproducible results over time