Add edm4eic::Jet

[ruse-traveler]

Briefly, what does this PR introduce?

Following the discussion in #88 , this PR introduces edm4eic::Jet. This type, inspired by the fastjet::PseudoJet, aims to represent jets in our data model in a more adequate way than edm4eic::ReconstructedParticle.

Note these 3 design choices:

• Only edm4eic::ReconstructedParticle are allowed as constituents, which places jet reconstruction in the final stages of reconstruction,
• No substructure quantities are represented in the type, which defers them to analyses,
• And the one-to-many relation jets allows for either the indication of/connection to sub-jets, seed jets (which may be deployed in background-subtraction algorithms), or background jets (e.g. off-axis cones).

What kind of change does this PR introduce?

• Bug fix (issue #__)
• New feature (issue Proposal for a Jet Type #88 )
• Documentation update
• Other: __

Please check if this PR fulfills the following:

• Tests for the changes have been added
• Documentation has been added / updated
• Changes have been communicated to collaborators

Does this PR introduce breaking changes? What changes might users need to make to their code?

No.

Does this PR change default behavior?

No.