Add global rule for -keepattributes Exceptions

R8 full mode requires an explicit keep rule for keeping attributes for a
given target (class/method/member). As such, we can set the global rule
for keeping these attributes with minimal cost while reducing the
maintenance burden for adding incremental keep rules.

For a typical Android build, this adds <20KB total to the image.

Bug: 215530220
Test: m
Change-Id: Iad3de32e27da0ca93b618d8a203ee65bae0bb5d1