feat: add leverage/Params.max_share_trigger proto

[robert-zaremba]

Description

We need a leverage module parameter to solve a cold start / bootstrap problem for tokens with limited max_supply and max_collateral_share.

Ref:

• Limit token supply (token.MaxSupply) #1227 (comment)
• https://www.notion.so/Initial-token-settings-for-x-leverage-afcde23e5b2f404bb957ef00b09cb5ac

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[robert-zaremba]

1 was not used.
Open for suggestions for a better name for this param.

[toteki]

This should wait until v4, as it is not required for mainnet release.

[adamewozniak]

This should wait until v4, as it is not required for mainnet release.

agreed

[robert-zaremba]

@adamewozniak , @toteki I prefer to have stable proto. This PR doesn't add new functionality. But we will need to use it as soon as we will enable Axelar.
Also, see: https://umeeworkspace.slack.com/archives/C03CVS0459A/p1663499718056569

[stale]

This PR has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[robert-zaremba]

I'm going to extract the docs imprvements from this PR and move it to a new PR.

[stale]

This PR has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This PR has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This PR has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.