`lox-time` Tracking Issue

[helgee]

• Implement parser for NAIF leap seconds kernels in lox-io (Enable LSK kernel parsing in lox-io #98)
• Implement LeapSecondsProvider trait and BuiltinLeapSeconds/Lsk impls (working title) in lox-time (Implement LeapSecondsProvider trait with builtin and LSK impls #99)
• Dismantle lox-eop and move the IERS parser to lox-io and the tidal model to lox-earth (Split up lox-eop #100)
• Reimplement IERS interpolation based on CubicSpline interpolator (Implement DeltaUt1Tai provider #101)
• Refactor transformations (Refactor time scale transformations #102)
• Complete Python API (Implement new Python API for lox-time and add TryToScale trait #103)

CC: @AngusGMorrison