855 hi update packet definition xtce (IMAP-Science-Operations-Center#…

…1187)

* Add combined HI 45/90 xtce file generated from TLM spreadsheets
Remove Hi L0 decom as this is now done entirely with packets_to_datasets
Point L1A at new xtce file and add Hi 90 APIDs

* Add new Hi 90 sample L0 data
Point l1a and l1b tests at new sample L0 data
Fix issues with histogram (SCI_CNT) decom issues after packet definition change

* Get sci_de decom working for now. Validation will likely uncover some bugs.

* Remove Hi L0 from code documentation