Add more finding options to KerrGeoFindResonance

[TVTien83]

I added more options for finding resonance orbit to the existing KerrGeoFindResonance:

• Find r- $\phi$ resonance and $\phi$ - $\theta$ resonance; with given ratio, a and two of (p, e, x).
• Find triple resonance with given ratio and (a, e).
• If there is no triple resonance, there will be a message for range of possible r-integer, $\phi$ -interger and $\theta$ -integer. To get a triple resonance from the wrong one, you can change one of 3 integers by picking one value in the corresponding interval from the message and keep the other 2.

Quick guide: The syntax is similar to the existing KerrGeoFindResonance, I just modify and add things to this:

• Same as in r- $\theta$, for r - $\phi$ and $\phi$ - $\theta$, set the $\theta$ - integer and r-interger to zero, respectively
• For triple-resonance, only give (a, e) and set of non-zero integer.
• For retrograde orbits, remember to use negative integers for $\theta$ and $\phi$ input; for example:
  KerrGeoFindResonance[<|"a"->0.9, "e"->0.5, "x"->-0.6|>, {1, 0, -2}].
  This helps keeping the solution unique in some KerrGeoFindResonance options.

Caution:

• The correction result might be too close the separatrix, which makes the frequency ratio diverges; the resonant equation is unsolvable. When it happens, I set the result to KerrGeoSeparatrix[a,e,x]+10^(-5). Try to choose set of integers not far from each other, since they tend to coincide as $p$ goes to infinity.