Properly document each and every build dependency of ColumnStore

People seem to be spending a lot of time on ColumnStore build & packaging issues. Some of the time is wasted because the build dependencies of ColumnStore are not clearly defined.

The building phase is marked TODO in https://github.com/mariadb-corporation/mariadb-columnstore-engine/blob/develop/BUILD.md

Source code contains a binary (sic!) version of a specific libjemalloc.so (filed at https://jira.mariadb.org/browse/MDEV-24124).

The CI pipeline at https://github.com/mariadb-corporation/mariadb-columnstore-engine/blob/develop/.drone.jsonnet does a lot of slimming down of the build flags.

These are signs that the current state is quite unclear.

It should be documented:

• What exactly are the external build dependencies? On a clean system, what should be installed in addition to the MariaDB Server and ColumStore sources?
• How does ColumnStore depend on MariaDB Server?
• Is it enough to have the sources available, or does it actually need to build MariaDB fully or partially?
• If partially, which plugins and storage engines must be built?
• Which of the following MariaDB Server CMakeLists.txt includes need to run?

INCLUDE(misc)

INCLUDE(mysql_version)

INCLUDE(cpack_source_ignore_files)

INCLUDE(install_layout)

INCLUDE(submodules)

# Add macros

INCLUDE(character_sets)

INCLUDE(cpu_info)

INCLUDE(zlib)

INCLUDE(ssl)

INCLUDE(readline)

INCLUDE(libutils)

INCLUDE(dtrace)

INCLUDE(pcre)

INCLUDE(ctest)

INCLUDE(plugin)

INCLUDE(install_macros)

INCLUDE(systemd)

INCLUDE(mysql_add_executable)

INCLUDE(symlinks)

INCLUDE(compile_flags)

INCLUDE(pmem)