- ABIs changed the field names of maps from "key" and "value" to "first"
and "second".
- `eosio-cpp` has been renamed to `cdt-cpp`
- abigen is part of `cdt-cpp` and no longer a seperate build step
- Note: there appears to be a bug in the ABI generation when using
version 4.0.0, so we stick with 3.1.0 for now

it used to be on a global config level

it serves as a nonce for transactions with a raw signature, but there
is not need to have it as an action paramter

only the active and the last batch of a campaign can be deleted for
now. else the campaign could end up in a dead lock

we are looking for a way to keep submissions in the same order as
reservations. previously the code falsely assumed that
`available_primary_key` would never re-use keys, but it appears EOS
does (it takes highest_primary_key + 1). this was causing collisions
between submissions IDs

it appears to be an offset-by-1 issue, so this is an attempt to remedy that

there was a change in the output of nodeos RPC calls, where maps
changed from "second" to "value" to refer to their value paramter

these structs where solely needed to generate signature for BSC
addresses, which has now been deprecated

it is not used anymore in V2

the field can also no longer be optional, as this is not needed with
the new split between reservations and submissions.

To achieve this, we have to keep track of the active batch for each
user inside `acctaskidx`. This means existing `acctaskidx` data will
be corrupted and must be purged.

before we were storing a uint64 (concatenation of campaign_id and
batch_idx). but as campaign_id is already present, we can save space
by just storing batch_idx. it is also more convenient for clients, as
there is no need to disect the batch_id in order to find the batch
index.