Jet/MET updates for R22 AnalysisBase

This makes a few updates which are needed to build AnalysisBase in release 22 (see ATLASG-1549), particularly the Jet/MET analysis algorithms. Changes are:

• Added Jet and MET analysis algorithm packages to AnalysisBase.
• JetCalibrationAlg now uses the new jet calibration interface. No preselection or out-of-validity handling is needed, so these are removed.
• METHelpers.h has been reinstated, for functions like buildMETSum(...). These had been moved into METMaker and METRebuilder, but had no dependence on the actual classes and are more useful to have independently. I've also propagated this to other packages which were using the class-based functions.
• The handling of MissingETAssociationMap has been updated to use our release 22 interface with the new helper class in METMakerAlg.
• METSignificance has been ported from release 21. The option for Run-1-style handling of the JER has been removed, as it was obsolete. WIP: I'm still having some trouble getting this to compile properly as it introduces several new dependencies. In particular I can't seem to get it to find (at least) ElectronPhotonFourMomentumCorrection/​EgammaCalibrationAndSmearingTool.h despite including that package in CMakeLists.txt. Generally I wouldn't want to include a concrete tool header like that, but it contains a needed function which just lives in the xAOD namespace for some reason (xAOD::get_eta_calo(...)).
• Made combinedP4FromRecoTaus::getCaloResolution(...) public in tauRecTools, as it's required for the MET significance calculation. It was public in the past, and presumably someone changed it not knowing there was an external dependence.

@krumnack - Maybe you want to take over from here, since you can probably figure out the remaining dependency issues more easily than me (or at least point out the issue, as I'm a bit stumped)? I've just been attempting to compile it in the current Athena (as opposed to AB) since METUtilities is also needed there.

Tagging also @khoo, @sawyer, @cdelitzs, @sschramm (and @mswiatlo since he's taking over for Steven soon) for their awareness.