feat: support DCA during rebalance in Ekubo Vaults [WIP]

[akiraonstarknet]

Problem

if a vault holds significant liquidity in the network (i.e. 50%), instantly removing liquidity and doing swap can cause significant slippages. Slowly swapping will allow enough time in the market to absorb sale without much slippage.

Solution

1. Add a new storage called old_bound_settings: Bounds
2. new struct DCASettings:
   a. liquidity_per_block => DCA must finish within these blocks
3. Add a new storage called dca_settings: DCASettings
4. Add an additional rebalance function as fn rebalance_with_dca(ref self: ContractState, new_bounds: Bounds, liquidity_bps_per_block: u64) -> Only registers a rebalance intent, doesn't do rebalance. (Note: liquidity_bps_per_blocks is liquidity % per block, denoted in bps. so, 1bps is 0.01% liquidity)
   a. relayer only
   b. updates old_bound_settings to current bound_settings
   c. writes new_bounds to bound_settings
   d. writes to dca_settings storage with start_block as current block number. liquidity_bps_per_blocks = total_liquidity_in_old_bounds * liquidity_bps_per_blocks / 10000
   d. Emits RebalanceWithDCA event:
   d.1. pool_key
   d.2. old_bounds
   d.3. new_bounds
   d.4. dca_settings: DCASettings
5. add new fn execute_dca_rebalance(swap_params: AvnuMultiRouteSwap)
   a. Relayer only (may not be required, but good for safety)
   b.