Build and distribute the RNP, Botan, json-c libraries as imported into third_party with bug 1621782

These are missing defines and a few functions that are used by
the RNP library but are not part of the Microsoft runtime.

dirent.h is an MIT licensed "header" file that contains opendir(),
readdir(), and closedir() for Windows. Copyright and license are
included in the file itself.

sys/time.h contains an implementation of gettimeofday() for Windows
that's used in rnp/src/lib/crypto/s2k.cpp.

Script and moz.build configuration for Botan for use in Thunderbird.

Runs Botan's configure.py with the desired options to generate a usable
build.h.

Pushed by thunderbird@calypsoblue.org:
https://hg.mozilla.org/comm-central/rev/ca5a694350fb
Compatibility headers for building RNP with clang-cl. r=kaie
https://hg.mozilla.org/comm-central/rev/a00ef189a6d3
Build configuration for zlib. r=kaie
https://hg.mozilla.org/comm-central/rev/925ba48a774c
Build configuration for Bzip2. r=kaie
https://hg.mozilla.org/comm-central/rev/006dc085c52e
Build configuration for Json-c. r=kaie
https://hg.mozilla.org/comm-central/rev/ce145705013d
Build configuration for Botan. r=kaie
https://hg.mozilla.org/comm-central/rev/a6d09372afd0
Build configuration for RNP. r=kaie
https://hg.mozilla.org/comm-central/rev/b1139f8617d4
Build configuration for OpenPGP libraries. r=kaie
https://hg.mozilla.org/comm-central/rev/7c06681d8e9a
Enable building OpenPGP libraries and include in distribution. r=darktrojan