feat: min liquidity limit in omnipool::add_token

[Roznovjak]

This PR also adds existential_deposit method to Inspect trait.

[github-actions[bot]]

Crate versions that have been updated:

• runtime-integration-tests: v1.20.2 -> v1.20.3
• pallet-asset-registry: v3.2.1 -> v3.2.2
• pallet-circuit-breaker: v1.1.21 -> v1.1.22
• pallet-dca: v1.4.3 -> v1.4.4
• pallet-omnipool: v4.1.5 -> v4.1.6
• pallet-omnipool-liquidity-mining: v2.1.4 -> v2.1.5
• hydradx-adapters: v1.3.0 -> v1.3.1
• hydradx-runtime: v228.0.0 -> v229.0.0
• hydradx-traits: v3.2.0 -> v3.2.1

Runtime version has been increased.