optimize btagbtvdeep::seedingTracksToFeatures re DeepVertex (or deep flavor+vertex combined) tagging

[slava77]

as a part of #31988 (#31988 (comment)) we find that the btagbtvdeep::seedingTracksToFeatures is pretty expensive.
At a quick glance, its implementation is rather suboptimal and can be sped up by caching relevant data per track instead of recomputing it in a nested loop over tracks.

https://legianni.web.cern.ch/legianni/cgi-bin/igprof-navigator/testMINI+bTag/cpu1K/276
may be of help, in addition to the code itself

@leonardogiannini

[slava77]

assign reconstruction

[cmsbuild]

New categories assigned: reconstruction

@slava77,@perrotta,@jpata you have been requested to review this Pull request/Issue and eventually sign? Thanks

[cmsbuild]

A new Issue was created by @slava77 Slava Krutelyov.

@Dr15Jones, @dpiparo, @silviodonato, @smuzaffar, @makortel, @qliphy can you please review it and eventually sign/assign? Thanks.

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[jpata]

type performance-improvements

[jpata]

type btv

[jpata]

@leonardogiannini what's the status here?