Made necessary updates to the employment alignment

[Mariia-Var]

-ensure ACMales, ACFemales and SingleDepMales, SingleDepFemales employment rates are aligned correctly

@LiangShi369, feel free to review the changes I made to employment alignment:
-included updated employment targets for 7 categories of BU (couples, singleMale, singleFemale, singleACMale, singleACFemale, SingleDepMales, SingleDepFemales)
-ensured we have alignment processes set up for these 7 categories of BU
-also, cleaned up some files and variable names

@justin-ven @Mariia-Var. I corrected typos in Statistics3 Class mentioned earlier, and all integration tests pass. I notice that during the alignment for some categories, the root finding procedure ends up with boundary solutions. Shall we worry about this at this stage? I can implement some checking and fix basing on the current version of model.

[justin-ven]

@Mariia-Var Boundary solutions are often an issue - I will add a new issue so that we can come back to this - well done!

[Mariia-Var]

@justin-ven , @LiangShi369
The comment “the root finding procedure ends up with boundary solutions” was added by Liang.

Yes — that is exactly the issue I spent some time investigating. It seems to occur only when aligning employment for one BU category - SingleDepFemale, while it works fine for all other categories, including SingleDepMale.

At first, I thought I might have missed a typo, so I asked Liang to take a look as well. Probably he also didn’t find any possible error there..

I agree that we can create an issue and come back to it later; however, if Liang has any further ideas or checks in mind, it may still be worth trying them now.

[Mariia-Var]

@justin-ven , @LiangShi369
I think we can approve this PR, as it is merging "MV-fix-EmploymentAlignment" to "develop_LS_PortEmploymentAlignment". And once David finishes with the integration of the new estimates into the develop branch, we can then merge "develop_LS_PortEmploymentAlignment" into the develop.

[LiangShi369]

@Mariia-Var @justin-ven I am investigating the boundary solutions in root searching. The cause is more than just typo -- solution requires some structural changes in activity alignment class. Will keep you updated. Meanwhile, shall we open another pull request or stay in this #331 ?