Even though I think that mysql_upgrade is a client package (it depends
on the mysql client and it's in the "client" directory in the source
tree, for instance), upstream laid it out differently. Since upstream
commit ec586f5 mysql_upgrade is to be considered a part of the server,
because the COMPONENT argument in the MYSQL_ADD_EXECUTABLE macro is set
to "Server".

That means that mysql_upgrade is only installed when the server is. So
we need to move it back to the server package, otherwise we will have a
build failure when mariadb-client is selected while mariadb-server is
not. This particular build failure was recently a topic on
openwrt-devel.

Some more binaries are moved, following the layout visible in
"man/CMakeLists.txt", to make sure we follow upstream's vision with
regards to how the binaries are packaged.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>