Custom bids duration

[dusan-maksimovic]

Description

Closes: #142

This PR introduces a bid_duration field on the Proposal to specify for how many rounds the liquidity is requested. If user votes with a lock for a proposal spanning across multiple rounds, it will not be allowed to vote with the same lock in the next rounds until the round in which the liquidity is clawed back from the 'long lasting' proposal. Max bid duration is stored in config and can be updated by the whitelist admins.

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Author Checklist

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I have...

• Targeted the correct branch
• Included the necessary unit tests
• Added/adjusted the necessary interchain tests
• Added a changelog entry in .changelog
• Compiled the contracts by using make compile and included content of the artifacts directory into the PR
• Regenerated front-end schema by using make schema and included generated files into the PR
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• Confirmed all CI checks have passed

[p-offtermatt]

Very nice! I added a few comments.

Also, I think it would be good to have a test case to confirm that it is possible to switch ones vote during the round, even when voting for an extended-duration proposal.

could easily be added as part of the test you added I think

[p-offtermatt]

Awesome!