* debt shares class is mostly done
* issuer changes mostly done
* feepool changes mostly done
* tests cleaned up a little bit

biggest thing still needing finalization is function to "transfer" debt to layer 2

Removed some functions it turns out we don't need

found one bug during testing in `sharePercentOnPeriod` function

the `interact` hardhat task has been refactored and moved
into its own package, `hardhat-interact`. This PR removes the old
code from the repository and uses the new package.

`synthetix` uses a custom system for managing deployments of its
contracts. To account for this, the `interact` command has been
extended to first regenerate the deployment manifests into a compliant
format.

Since `hardhat-interact` relies on hardhat configuration for network
and signer configuration, the `hardhat.config.js` file has been updated
to include our networks.

notes:
* package-lock.json verification may fail because of new NPM 8 format.
how do we work around this?

* debt shares class is mostly done
* issuer changes mostly done
* feepool changes mostly done
* tests cleaned up a little bit

biggest thing still needing finalization is function to "transfer" debt to layer 2

Removed some functions it turns out we don't need

found one bug during testing in `sharePercentOnPeriod` function

…h interact

…synthetix into sip-185-debt-shares

…synthetix into sip-185-debt-shares

* rename `_supplyBalance` to `_increaseBalance`
* use uint128 for storage types to save writes
* add return type for transfer functions
* split up some lines

* fix test mislabel
* fix warnings

v3 has requested to be able to use the snapshotting capability of this contract to track elections and governance.
This required the following minor changes:

* ability to delegate access to `takeSnapshot` (which was renamed from `setCurrentPeriodId` for clarity)
* feePeriodId must be a timestamp now

…hase

required for 165