* feat(provider): allow specifying a default polling interval param
This parameter is going to be used for all subsequent client calls by default. It can still be overriden with the internal
`interval` calls
* feat(contract): replace reference to Client with Arc
* feat(abigen): adjusts codegen to use Arcs
* fix(ethers): adjust examples to new apis
* fix(provider): return TxHash instead of PendingTransaction on tx submission
Returning a PendingTransaction allowed us to have nice ethers.js-like syntax where you submit
a transaction and then can immediately await it. Unfortunately, now that we use Arcs and not lifetimes
this meant that we would need to bind the function call in a variable, and then await on it, which is pretty
bad UX.
To fix this, we revert back to returning a TxHash and introduce a convenience method on the provider and the
contract which takes a tx_hash and returns a PendingTransaction object. The syntax ends up being slightly
more verbose (although more explicit), but the issue is fixed.
Georgios Konstantopoulos