Move a few packages from core_minimal.mk to base.mk.

All the products that inherit from base.mk add these packages, so moving
them up the hierarchy eliminates some duplication.

    DownloadProvider
    idmap
    libneuralnetworks
    mdnsd
    MediaProvider

Bug: 80410283
Test: diff all product variables with multiproduct_kati
Change-Id: I133a385b3bc64261d73f616c416f7a905675c09d
Merged-In: I133a385b3bc64261d73f616c416f7a905675c09d