Replace deprecated usage of AddressFromBech32 with address.Codec

[gjermundgaraba]

We use a few different versions of *AddressFromBech32 in the code base, which is now deprecated. This should be replaced with use of an address.Codec as per the documentation:

// Deprecated: Use an address.Codec to convert addresses from and to string/bytes.
func AccAddressFromBech32(address string) (addr AccAddress, err error) {

Replace all the instance of these deprecated functions.

Look at how this is done in the SDK for a good pointer on how it should be done here.

[gjermundgaraba]

@duvbell, I added a link to the SDK where you should go look for the different ways they get the correct codec at any given time. It is usually attached to a client context, so you shouldn't have to create it anywhere yourself.

If you want to work on this issue I can assign it to you (that's usually what we want before a PR, so people don't overlap work).