Fixed AQGD optimizer groups objective function calls by default

[proeseler]

Summary

Fixes #50

It has been fixed that the AQGD optimizer groups objective function calls by default.

Details and comments

The number of requests is chunked in a similar way to the gradient_num_diff() method from the Optimizer class. The number of grouped evaluations can be controlled via the max_grouped_evals parameter now and a test has been added to check whether the new functionality works for a parallelizable and a non-parallelizable objective function.

[CLAassistant]

All committers have signed the CLA.

[woodsp-ibm]

Note: CI is failing here for Python 3.12 - see #113

As to Algorithms Unit Tests / Monitor_Qiskit_Main (ubuntu-latest, 3.8) this is one a pair that test against the main branch in Qiskit, rather than stable release, so we can monitor for breaking changes as Qiskit develops. Neither of this monitor pair are required to pass for the PR (you can see they do not have the Required label. But it is something that will need investigating as to why this is happening as there should not be breaking changes like this - it just recently started it seems, the #113 has been going on a few days.

[coveralls]

Pull Request Test Coverage Report for Build 7583049769

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.08%) to 90.66%

---

Totals
Change from base Build 7583003400:	0.08%
Covered Lines:	6484
Relevant Lines:	7152

---

💛 - Coveralls

[ElePT]

The changes look good to me, thanks @proeseler for the contribution. I'll approve but wait for @woodsp-ibm's confirmation before merging.

[woodsp-ibm]

Thanks for doing this and taking care of the comments. It all looks good to me - sorry for the delay in getting back and reviewing this.