Replaces libpcre with libpcre2

libpcre was removed and libpcre2 10.21 was added instead.

The files of the c++ wrapper library, libpcrecpp, were moved to
their own directory, pcrecpp. As of this patch pcrecpp is broken
due to the missing dependency libpcre. The port will be added in
a subsequent commit to better document the changes made.

Bug: 24091652
Change-Id: Iac638baa545470596cc764271ae94d6b95ebede8
636 files changed