Adding elliptical weak lensing profiles

[calumhrmurray]

Code to compute the shear_t, shear_x and convergence profiles for elliptical profiles following the equations in Adhikari et al. 2014 (https://arxiv.org/pdf/1407.1128.pdf).

[rancesol]

Goals for triaxial working group at clcosmo-retreat (july-2023): #CL

• build an issue branch
• make a working folder in the examples directory of CLMM
• make a mock catalog (small) to test on using the Oguri 2D density profile
• write scripts to perform the Adhikari computations
• add higher order terms in ellipticity to the above scripts
• fit halos back to the Oguri profiles
• test the performance
• optimize for larger datasets

[shenmingfu]

Instead, we use the Shin computation.
We divide into 2 groups:

• Compute delta_sigma_4theta, delta_sigma_constant, cross terms from the mock catalog (sums, weights, etc).
• Compute theoretical values of the above terms (integrals, etc.).