[Popper] Add popperRef prop

[oliviertassinari]

Closes #15802.

These changes are extracted from #15703:

• First, the Popper.js instance is now persisted between two renders (perf fix). You gonna like this one @eps1lon. We were using {} as default prop value. This is a new reference at each render. Most of the time, it's fine. The problem, in this case, is that we are using the value as an effect dependency. It reruns systematically. I have noticed it with a poor slider update performance.
• It exposes a popperRef prop that behaves like a reference. It can be used to programmatically update the position of the popper, e.g. when the slider's thumb value changes.

[mui-pr-bot]

Details of bundle changes.

Comparing: 41f1722...d62b730

bundle	parsed diff	gzip diff	prev parsed	current parsed	prev gzip	current gzip
@material-ui/core	+0.07% 🔺	+0.09% 🔺	319,427	319,665	87,505	87,586
@material-ui/core/Paper	0.00%	0.00%	67,964	67,964	20,210	20,210
@material-ui/core/Paper.esm	0.00%	0.00%	61,258	61,258	19,019	19,019
@material-ui/core/Popper	+0.83% 🔺	+0.65% 🔺	28,728	28,966	10,349	10,416
@material-ui/core/Textarea	0.00%	0.00%	5,513	5,513	2,373	2,373
@material-ui/core/TrapFocus	0.00%	0.00%	3,755	3,755	1,577	1,577
@material-ui/core/styles/createMuiTheme	0.00%	0.00%	16,016	16,016	5,820	5,820
@material-ui/core/useMediaQuery	0.00%	0.00%	2,529	2,529	1,087	1,087
@material-ui/lab	+0.17% 🔺	+0.18% 🔺	138,362	138,600	42,526	42,601
@material-ui/styles	0.00%	0.00%	51,384	51,384	15,186	15,186
@material-ui/system	0.00%	0.00%	14,825	14,825	4,240	4,240
Button	0.00%	0.00%	83,893	83,893	25,495	25,495
Modal	0.00%	0.00%	20,343	20,343	6,690	6,690
colorManipulator	0.00%	0.00%	3,904	3,904	1,543	1,543
docs.landing	0.00%	0.00%	55,089	55,089	13,848	13,848
docs.main	+0.04% 🔺	+0.05% 🔺	652,739	653,006	206,467	206,576
packages/material-ui/build/umd/material-ui.production.min.js	+0.08% 🔺	+0.08% 🔺	292,892	293,117	83,438	83,504

Generated by 🚫 dangerJS against d62b730

updated

This one was a hard one for me!

[eps1lon]

Keep forgetting I have pending reviews.