Split irods_common_core and irods_lib_core_[client|server] into separate directories.

[SwooshyCueb]

The irods_common_core and irods_lib_core_[client|server] targets are defined in lib/core:

irods/lib/core/CMakeLists.txt

Lines 19 to 20 in e4b4e8a

	add_library(
	irods_common_core

irods/lib/core/CMakeLists.txt

Lines 202 to 203 in e4b4e8a

	add_library(
	irods_lib_core_${variant}

Let's split them into separate directories.

Some decisions will need to be made:

• Whether irods_common_core or irods_lib_core_[client|server] will remain in the core directory
• What the new directory shall be named
• What the new target names shall be

There may also be headers that do not clearly belong to one or the other.

[trel]

presumably we have a common because there are things for both? why split them? because composability is easy/good?

[SwooshyCueb]

irods_common_core is an object library used to make libirods_common.
irods_lib_core_client and irods_lib_core_server are two object libraries made from the same source files used to make libirods_client and libirods_server, respectively.
It doesn't make sense to me to have them live in the same directory.

[trel]

fair enough - if we're building the same targets in the end... nobody downstream needs to know/care i presume...