Remove the obsolete FEATURE_SET cmake option.

Do not make any WITH_SSL, WITH_ZLIB or WITH_ICU settings in
feature_set.cmake, it only obfuscates what the real defaults are.

Add a new argument DEFAULT_LEGACY_ENGINE to the MYSQL_ADD_PLUGIN macro,
and use this for the ARCHIVE, BLACKHOLE and FEDERATED plugins.
Move the cmake code for ON|OFF|WITHOUT|WITH for these plugins from
feature_set.cmake to MYSQL_ADD_PLUGIN.

With this, feature_set.cmake be removed entirely.

For each lib: SSL ZLIB ICU
 - Move INCLUDE_DIRECTORIES ... to <lib>.cmake
 - Move building of libraries   to <lib>.cmake
 - Move default settings for WITH_<lib> to within each MYSQL_CHECK_<lib> macro.

Cleanup some obsolete cmake code for the FEDERATED engine.
Change-Id: I3264e484e89f2b1faf00e1b52ec4bf6151790aec