WIP: Ecc bank with phenom ecc waveform

[bhooshan-gadre]

Stocastic eccentric bank:

• Here is a working code for ecc stochastic bank for Phenom ecc approximant.
• I have marked WIP as the approximant is not available and cannot be tested with the current lalsuite.
• Also, there is a possibility of getting rough metric matches to improve the bank generation. Maybe that will be a separate PR?

[spxiwh]

THanks @bhooshan-gadre . Skimming over this, it definitely looks like there's a number of different changes in here (e.g. including XAS should be separated from any eccentric stuff, there's a lal file pulled into here, the rough metric matches). Can these be pulled off for ease of review? (Also we would have to wait for the eccentric waveform to be in a lal release before we can really include it here).