Revise `contactfinder` and `eclipsefinder` modules to accept an arbitrary time-array over which the discrete contact events can be evalulated.

[vinay0000]

Currently the times at which the contacts/eclipses are evaluated are over the times available in the input StateSeries object of the spacecraft.

[vinay0000]

This has been done for the eclipsefinder module in the commit (vinay_dev branch): 2985ee1