drop deprecated TBB components (#6590)

Quite some time ago, many of the TBB components were deprecated in favor
of their near-equivalents in the STL or, in the case of task_scheduler_init,
were broken up and reconstituted under a less ad-hoc logic. Every time a header
file marked deprecated gets included, a rather loud warning is emitted, which
leads to a complete TBB's domination over the stderr stream during build time,
making it harder to notice _legitimate_ warnings.

Instead of merely muting the output with TBB_SUPPRESS_DEPRECATED_MESSAGES,
perform a genuine migration away from the deprecated components with the added
benefit of achieving a source compatibility with oneTBB, the successor to TBB
which has dropped the deprecated API for good.

What got replaced for what?

| Deprecated				| Replacement					|
| ------------------------------------- | --------------------------------------------- |
| `tbb::atomic`				| `std::atomic`					|
| `tbb::mutex`				| `std::mutex`					|
| `tbb::mutex::scoped_lock`		| `std::scoped_lock<std::mutex>`		|
| `tbb::mutex::scoped_lock` (empty)	| `std::unique_lock<std::mutex>` (deferred)	|
| `tbb::task_scheduler_init`		| `tbb::global_control`				|
| `tbb::this_thread`			| `std::this_thread`				|

Signed-off-by: Roman Beranek <roman.beranek@prusa3d.com>

src/libslic3r/PrintObject.cpp

@@ -22,7 +22,6 @@
 #include <boost/log/trivial.hpp>
 
 #include <tbb/parallel_for.h>
-#include <tbb/atomic.h>
 
 #include <Shiny/Shiny.h>