CURA-12016 improve loading time with many printers

[wawanbreton]

This PR provides 2 changes:

• Disable the garbage collector while loading cached containers from pickled files. This makes the loading twice as fast, which is significant because we do it multiple times with large containers
• Set the proper container sub-type in the metadata so that we can properly filter on sub-types (necessary for CURA-12016 improve loading time with many printers Cura#20813)

CURA-12016

[github-actions]

Test Results

2 407 tests  ±0   2 392 ✅ ±0   22s ⏱️ -1s
    1 suites ±0      15 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit cf37631. ± Comparison against base commit 66fa8ac.

[rburema]

I wonder if we can (temporarily) disable the gc 'more generally' than just that piece of code -- there must be other tasks where that's in the way.

[wawanbreton]

I wonder if we can (temporarily) disable the gc 'more generally' than just that piece of code -- there must be other tasks where that's in the way.

Probably indeed. It seems to really be beneficial when a piece of code instanciates or releases a lot of objects. Right I don't see an obvious part where this happens, but we can definitely keep it in mind.