Consider allowing funding pool with erc20 transfers

[Corantin]

Reasons:

• way more flexible (would support streaming or direct erc20 transfer)
• allo.fundPool not usefull: only reason is allo protocol fee but allo is not collecting fee on any supported chains
• more reliable if someone still decide to make a erc20 transfer
• can be hooked with external protocols more easily (like gardens v1)

Change impacts:

Contract:

• change getPoolAmount to return balance of the token
• replace totalAmount field to getter function call
• remove PoolAmountIncreased

Subgraph:

• Remove any reference to poolAmount in mapping and schema

Frontend

• only place that is using the subgraph field totalAmount
  

[Corantin]

Mea culpa: The subgraph poolAmount is updated when a proposal is executed through the Distributed event

[Corantin]

Freezing this for now cause after double check, the flow is working.
Other reason is we would not be able to use Allo as the centralized TVL record contract