Remove Exit Fee parameter from pools

[JohnnyWyles]

Proposal 429 recently passed to remove the Exit fee parameter from all existing and new pools at a future software upgrade.

During removal, all pools with Exit Fee settings will have it removed and no future pools will be able to add one.

Affected pools
553 - LIKE/OSMO
596 - BOOT/ATOM
555 - LIKE/ATOM
905 - DYS/OSMO
597 - BOOT/OSMO
802 - ATOM/stATOM
654 - CRBRUS/HUAHUA
595 - BOOT/ATOM
696 - GLX/OSMO
551 - LIKE/OSMO
552 - LIKE/ATOM
554 - LIKE/ATOM
652 - CRBRUS/OSMO
655 - CRBRUS/HUAHUA
657 - CRBRUS/HUAHUA
797 - UMEE/HOPE

Since the proposal Pool 926 has also been added, unlisted asset but believe that it is 8ball/OSMO

[p0mvn]

This has been addressed via #4767

We did not remove the fee but, instead, disabled pool creation with non-zero fee

The reason for this instead of full removal is that we would have to perform migrations. Migrating active pools is risky, and we would like to avoid doing that for all pools at once via upgrade handler