[LUM-576] Close pool feature

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Introduction

This Pull Request introduces a close pool feature, that can be triggered by the community using governance proposal.

It aims to properly stop and close a pool by following the given steps:

• Block deposits and other operations
• Launch a final 100% draw with the actual prize pool
• Initiate all withdrawals
• Once all the withdrawals have completed, and in case of remaining dusts, transfer it back to fee collector
• Flag the pool as closed

Every single step requires no human intervention and is relying over IBC / ICA callbacks, but can be re-triggered at some point in case of step failure.

Testing

Unit test has been added
Test is planned on dedicated upgrade network