WIP: migrate algorithms to use custom memory pool

Includes the commits of !2278 (merged) and !2270 (merged), uses the new tools provided by !2270 (merged) in HLT1 algorithms.

WIP reason: this MR will eventually only include DAQ/Velo/UT, but currently it includes everything.

mentioned in merge request !2270 (merged)

mentioned in merge request Rec!1845 (closed)

mentioned in merge request Phys!631 (closed)

added 1 deleted label

changed target branch from olupton_custom_allocators to master

changed the description

It seems that the nightlies couldn't cope with the relationship between this MR, !2270 (merged) and !2278 (merged). I changed the target branch to master here, which temporarily adds the contents of !2270 (merged) and !2278 (merged) to this MR.

• [2020-01-17 00:05] Validation started with lhcb-test-throughput2#263
• [2020-01-18 00:10] Validation started with lhcb-test-throughput2#264

removed 1 deleted label

mentioned in issue Moore#128 (closed)

added 37 commits

• 17e190ad...236b1e28 - 28 commits from branch master
• 12046441 - Prefer LHCb::span to std::vector const& as an argument type.
• fbe06b01 - Fix private member access from non-friend.
• 38d1c433 - Import Gaudi::Arena::Monotonic.
• 591b50de - Add LHCb-specific EventContext extension.
• e97e1db4 - Add LHCb::Allocators::{Memory,MonotonicBuffer}Resource.
• 2308d6ab - Add LHCb::Allocators::EventLocal<T>
• 16857c58 - Create and use an event-local memory pool in the scheduler.
• 8fca6a59 - Add memory pool statistics to the standard list of exclusions.
• 93f712a6 - Memory pool algo migration.

Compare with previous version

Superseded by !2338 (merged), !2339 (merged), !2340 (merged), !2341 (merged), !2342 (merged) and !2343 (merged).

closed