Previously the basket size configuration could only be coarsely applied to all
branches but in most real world files the size of the data in each branch varies
significantly. Setting a small value causes large branches to be packed into
individual baskets and prevents effective compression. Setting a large value
improves the compression ratio of large branches but causes excessive memory
usage.

Instead we change the parameters to only specifiy the maximum and minimum
branch size and provide a target for the number of events to pack into each
basket. We then use the first event to estimate the size of the branch.

This makes the branching very sensitive to the first event size however this
seems to work okay in practice. If needed the basket sizes could be refined
after several events to give a more precise estimate.

See merge request !1391

See merge request !1393

See merge request !1390

See merge request !1389

See merge request !1388

See merge request !1387

See merge request !1386

See merge request !1384

When the static function TH1::SetDefaultSumw2 had been called (passing true), `Sumw2(true)` is automatically
called by the constructor of TProfile. This is a problem because in the profiles in Gaudi::Accumulators we do
not keep track of the sum of squares of weights and consequently don't set fBinSumw2 of the TProfile, which in
turn leads to a self-inconsistent TProfile object. The "fix" is to disable sum of squares explicitly.

See merge request !1385

See merge request !1383

See merge request !1382

See https://sourceware.org/bugzilla/show_bug.cgi?id=27653

See merge request !1377

Sebastien Ponce authored 2 years ago and Marco Clemencic committed 2 years ago

Separated RootHistogramSinkBase from RootHistogramSink so that this part is reusable for other sinks

See merge request !1379

See merge request !1375

See merge request !1371

Closes #237

See merge request !1376

Closes #233

See merge request !1374

See merge request !1373

See merge request !1372

See merge request !1370

See merge request !1369