Document and Calculate Weights for Pallets

[apopiak]

Issue to track progress on documenting weight for dispatch calls.

In order of benchmarking importance from Gav:

docs	weights	PR	owner	pallet
[x]	[x]	#5680	@apopiak	Identity
[x]	[x]	#5446	@shawntabrizi	Balances
[x]	[x]	#5593 #5775	@shawntabrizi	Timestamp
[x]	[x]	paritytech/polkadot#1036	@shawntabrizi	Polkadot/Claims
[x]	[x]	#5708	@shawntabrizi	Vesting
[x]	[x]	#5771	@thiolliere	Im Online
[x]	[x]	#5964	@shawntabrizi	Staking
[x]	[x]	#5738	@thiolliere	Session
[x]	[x]	#5845	@kianenigma	Elections Phragmen
[x]	[x]	#5828	@thiolliere	Democracy
[x]	[x]	#5802	@apopiak	Collective
[ ]	[x]	#5888 #5851	@tomusdrw @shawntabrizi	Offences
[ ]	[x]	#5723	@thiolliere	Treasury
[ ]	[x]	#5787	@shawntabrizi	Utility
[x]	low-prio	#5593	@apopiak	Assets
[x]	[x]	#5593 #5888	@shawntabrizi	System

[gui1117]

Should we extend this issue with information about:

Create sufficiently accurate weight formula, based solely on call data (not on state!), refactoring dispatches as necessary.
Implement weights through all pallets (FunctionOf).

for #4961

so each pallet should be: benchmarked, documented and have correct weight.

[kianenigma]

I'll grab one or two that I can manage.

[apopiak]

I'm noted down as owner for system, but likely won't be able to get to it in time. So please grab it.

[gui1117]

I take democracy but pallet is huge so if someone want to join I push my draft and we can divide extrinsics.