Implement a ThOr functor-based monitoring

Implements an algorithm that creates 1D histograms of any functor applied on track-like or composite objects. Small fix to the mass functor, so it works correctly with LHCb v1 particles.

A possible implementation of the monitoring (in the core of a line builder in lhcb/Moore>) is:

from PyConf.Algorithms import Monitor__ParticleRange

def monitor(name, particles, functor, *, histogram_name, range, bins=100):

    assert (len(range) == 2)
    config = dict(
        name=name,
        Input=particles,
        Variable=functor,
        HistogramName=histogram_name,
        Bins=bins,
        Range=range)
    bk = thor_backend()
    if bk == PARTICLE_V1:
        return Monitor__ParticleRange(**config)
    else:
        raise NotImplementedError(
            f'Monitoring not implemented for ThOr backend "{bk}"')


@register_line_builder(all_lines)
@configurable
def ks02pipi_line(name="Hlt2KS02pipiLine", prescale=1):

    pvs = make_pvs()
    pions = filter_decay_products(make_long_pions(), pvs)
    kaons = make_kaons('KS0 -> pi+ pi-', [pions, pions], pvs)

    mass_min, mass_max = 400. * MeV, 600. * MeV

    mass_monitor = monitor(
        f'{name}MassMonitor',
        kaons,
        F.MASS,
        histogram_name='mass',
        range=(mass_min, mass_max))

    return Hlt2Line(
        name=name,
        algs=upfront_reconstruction() + [kaons, mass_monitor],
        prescale=prescale,
    )

Related to LHCb!3278 (merged), Phys!997 (merged), Moore!1046 (merged)