feature: add all/most known aggregators and attacks

[srlt]

• including (where known) upper_bound, etc

[ArthurDanjou]

I've listed all the aggregators and attacks used in the list of the selected papers. We need to discuss to validate or not the implementation

Attacks

#	Name	Description	To Validate	Done
1	sign_flip / signflipping / SignFlipping	Invert gradient sign
2	label_flip / labelflipping / LabelFlipping	Flip labels on client side
3	mimic / Mimic	Mimic another worker's gradient
4	nan / NaN	Send NaN values	☑
5	signflipping	Variant of sign flip
6	scaledSF / scaled_sign_flip	Scaled sign flipping
7	mimic_heuristic	Heuristic mimic
8	empire	Empire attack	☑
9	anticge	Anti-CGE
10	identical_sparse	Identical sparse
11	identical	Identical gradients
12	dissension	Dissension
13	InnerProductManipulation / IPM	Scale mean by -tau
14	Optimal_InnerProductManipulation	Optimized IPM
15	ALittleIsEnough / ALIE / lie	Scale mean + tau * std	☑
16	Optimal_ALittleIsEnough	Optimized ALIE	☑
17	Inf	Send infinity	☑
18	Gaussian	Random gaussian noise
19	zero	Send zeros
20	noise	Add random noise
21	random	Random attack
22	byzMean	Byzantine mean
23	min_max / minmax	Min-max attack
24	min_sum	Min-sum attack
25	adaptive_std	Adaptive std attack
26	adaptive_sign	Adaptive sign attack
27	adaptive_uv	Adaptive UV attack

Aggregators

#	Name	Description	To Validate	Done
1	average / Mean / Average	Simple arithmetic mean	☑
2	median / Median	Coordinate-wise median	☑
3	trmean / TrMean / trimmed_mean	Trimmed mean	☑
4	krum / Krum	Krum aggregator
5	multikrum / MultiKrum / Multi-Krum	Multi-Krum	☑
6	bulyan / Bulyan	Bulyan	☑
7	geometric_median / GeoMed / GeometricMedian	Geometric median
8	dnc / DnC / divide_conquer	Divide and conquer
9	signguard / SignGuard	Sign guard
10	rfa / RFA	Robust federated aggregation
11	mom / MoM	Momentum-based
12	mva / MVA	Minimum variance averaging
13	mea / MEA	Mean estimation
14	cva / CVA	Coordinate-wise vector agreement
15	iter_cva / Iter_CVA	Iterative CVA
16	cenna / CENNA	Cross-entropy neural network aggregator
17	bucketing	Bucketing
18	bucketing_stress	Bucketing stress
19	brute / Brute	Brute force (= MDA)
20	aksel	Aksel	☑
21	cge / CGE	CGE
22	centeredclip / CenteredClipping	Centered clipping
23	filterL2	L2 filtering
24	krum_pseudo	Krum pseudo
25	multiKrum_pseudo	Multi-Krum pseudo
26	ios	IOS
27	robust_gossip	Robust gossip
28	MDA	Minimum Diameter Averaging	☑
29	MoNNA	MoNNA
30	Meamed	Mean around median	☑
31	CAF	Covariance-bound Agnostic Filter
32	SMEA	Smallest Maximum Eigenvalue Averaging
33	SignGuard-Sim	SignGuard simplified
34	SignGuard-Dist	SignGuard distant

[moh]

Note: build base class first for attacks and GAR, think in a way to make it easy to use by researchers (adding new components ...)