Create LHCb specific version of MergingMultiTransformerFilter.

See merge request !3274

Release notes and dependencies for LHCb v53r3

See merge request !3276

RefBot going live!

See merge request !3272

Migrate to LHCb::Algorithm

See merge request !3267

Spruce reports to RawBanks, further cleanup of HltDAQ

See merge request !3260

Move Packing related algorithms to Event/EventPacker

See merge request !3269

add support for TH3 reading from conditions DB

See merge request !3208

- and thus, impliclicitly, to Gaudi::Algorithm
- also, migrate away from UTAlgBase:
   - specify DeUTDetector as dependency
   - use ToolHandle for readout tool
- prefer standalone functions in anonymous namespaces over member functions

LHCbAlgs: add missing MultiTransformerFilter in LHCb::Algorithms namespace

See merge request !3266

- remove support for run1-style 'joined' Hlt1/Hlt2 RawBank SourceID
  concretely: there must now be a one-to-one correspondence between the
  sourceID, and the list of decisions that need to be decoded.
- remove unused HltTrackReports{Writer,Decoder}
- factor out SourceID enum so a single definition can be shared
- add support for `Property<SourceID>` and use that instead of
  `Property<int>` + updatehandler or checks in initialize
- given the above, decoder components no longer have
  include their corresponding writer header files
- amalgamate component header files into the corresponding source files
- migrate HltDiffHltDecReports to LHCb::Algorithm::Consumer
- make HltLumiWriter thread-safe
- prefer MsgCounter over Error(...) and Warning(...)
- prefer span over bare pointer
- start putting code in the LHCb::Hlt::DAQ namespace instead of
  adding `using namespace LHCb`

Release notes and dependencies for LHCb v53r2

See merge request !3265

Revert FTRawBankEncoder to produce raw event only

See merge request !3262

Remove workaround for gcc9

See merge request !3261

Rationalize names

See merge request !3255

Modernize & Tweak HltDAQ

See merge request !3257

- prefer LHCb::Algorithm over Gaudi::Functional
  (and, as a consequence replace Error(...) with MsgCounter<...>)
- throw error in case of overlapping keys between Hlt1 and Hlt2
- prefer `Property<std::array>` over `Property<std::vector>` with check
  that size is always 3...
- check for valid SourceID using an update handler instead in initialize

make DISABLE_TOOL to allow arguments

See merge request !3246

Add gcc11 and clang12 platforms to PlatformInfo

See merge request !3253

Fixes for DD4hep

See merge request !3119

Add missing header to get boost::hash in Boost 1.77

See merge request !3227

Remove implicit ordering assumption of LHCbIDs when converting to a v3::Track

See merge request !3249

- rename LHCb::Pr::FT::PrSciFiHits into LHCb::Pr::FT::Hits
- add a (deprecated) using statement for PrSciFItHits
- move {Hot,Cold}HitInfo types into the Hits scope