✨ [parallelisation] New groups and Store options

[acabarbaye]

Description

• new store option to be able to limit function to one single execution
• new store option to be able to set the number of workers executing in parallel
• A new group to execute contextual function
• Some more helpers

Test Coverage

• This change is covered by existing or additional automated tests.
• Manual testing has been performed (and evidence provided) as automated testing was not feasible.
• Additional tests are not required for this change (e.g. documentation update).

[joshjennings98]

Just a few small comments

[joshjennings98]

I think we have a misunderstanding about how the closeOnce should work