Manual cleanup of cmake code in router:

Use the target mysqlrouter_all consistently, remove the
MYSQL_ROUTER_BUILD_ALL_TARGET cmake variable.

Use th target mysqlrouter consistently, remove the
MYSQL_ROUTER_TARGET cmake variable.

Use the LINK_LIBRARIES and DEPENDENCIES arguments
of the function MYSQL_ADD_EXECUTABLE.

Remove FILE(GLOB_RECURSE ...) use explicit list of files instead.

Remove obsolete option WITH_HARNESS

Let MYSQL_ADD_EXECUTABLE add dependency for mysqlrouter_all
for executables with COMPONENT Router.

Cosmetics: line length, indentation, uppercase keywords,
split long lines in files changed by the above.

Change-Id: I54ae3b270f41cfd1f42c137b650aa42ccdb85f76