feat(token registry): proto max collateral share

[robert-zaremba]

Description

ref: #1095

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[toteki]

For clarity, what is an example of this in use?

Option 1 - If I'm understanding correctly:

MaxCollateralSupply(tokenA) = 20%

Each time collateral of token A is added to the system, the total USD value of all collateral
in the system is calculated. If the total USD value of all token A collateral in the system
would exceed 20% of the first value, `MsgAddCollateral` fails.

There might also be restrictions on `MsgRemoveCollateral` of token B, if removing
token B would cause token A to exceed 20% of system collateral value.

Option 2 - if I'm misunderstanding the wording, this was another possibility

MaxCollateralSupply(tokenA) = 20%

If the total supply of token A is 1000, then only 200 can be used as collateral until more
is supplied.

Am I correct in assuming this proposal is the first option?

[robert-zaremba]

For clarity, what is an example of this in use?

I will add ADR update once this will get merged with a proper example. Option 1 is the valid one - see the linked issue - it has more details.

There might also be restrictions on MsgRemoveCollateral of token B, if removing token B would cause token A to exceed 20% of system collateral value.

This is a good and valid point. The restriction will only hold when adding a collateral.

[toteki]

We might also solicit naming advice for this parameter in discussion tomorrow.

MaxCollateralSupply on its own suggests a limit to the amount of collateral itself, rather than a "ratio" or "share" of the total market.

[robert-zaremba]

MaxCollateralSupply on its own suggests a limit to the amount of collateral itself, rather than a "ratio" or "share" of the total market.

How about MaxCollateralSupplyRatio? Feel free to propose other names.

[toteki]

MaxCollateralSupply (wrong meaning)
MaxCollateralMarketShare? (too long)
MaxCollateralShare?

[robert-zaremba]

Renamed to MaxCollateralShare

[toteki]

Did a little housekeeping (see commits) - approving now.

[codecov-commenter]

Codecov Report

Merging #1096 (e6dbc18) into main (7d45ca6) will increase coverage by 0.27%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1096      +/-   ##
==========================================
+ Coverage   43.55%   43.82%   +0.27%     
==========================================
  Files          65       65              
  Lines        8390     8393       +3     
==========================================
+ Hits         3654     3678      +24     
+ Misses       4486     4472      -14     
+ Partials      250      243       -7     

Impacted Files	Coverage Δ
x/leverage/types/token.go	72.58% <100.00%> (+36.98%)	⬆️