Change to use Celery for satellite propagation; change response format; fix for making sure most recent satellite is used

[github-actions[bot]]

Coverage Report

File	Stmts	Miss	Cover	Missing
api/core
propagation_strategies.py	148	128	14%	81–186, 232–256, 317–417, 443–449, 452
utils.py	186	128	31%	38, 64–71, 74–81, 105–116, 160–172, 203–234, 285–351, 391–406, 464–465, 479–480, 489, 544–647, 680–681
api/core/database
models.py	49	12	76%	31–33, 36, 63–69, 72
satellite_access.py	32	23	28%	11–22, 26–39, 44–75
tle_access.py	67	32	52%	27–49, 70–88, 112, 127, 139, 150–151, 158–160, 170–175
api/core/versions/v1
routes.py	195	110	44%	42, 83, 134–140, 148–150, 215–216, 222–237, 286–336, 380–423, 471–523, 585–586, 590–605, 651–699, 721–743, 765–788, 828–877
tasks.py	148	111	25%	45–149, 157–250, 281–301, 341–360, 380–383, 404–407, 427–430
api/utils
coordinate_systems.py	36	28	22%	24–35, 55–70, 86–98, 117–131, 153–174
time_utils.py	21	18	14%	18–48, 66–92
TOTAL	930	590	37%

Tests	Skipped	Failures	Errors	Time
25	12 :zzz:	0 :x:	0 :fire:	48.192s :stopwatch: