feat(deployers): init pool script

[dleonard00]

There's not an good way to test new workflows. Merging this to be able to test it.

[PaulRBerg]

There's a couple of issues introduced by this PR.

• The "add liquidity" workflow is not a deployer. We have to either rename the deployers package to something else (e.g. tasks) or move all the "deployers" to the helpers package.
• The TASK_ADD_LIQUIDITY constant is not ordered alphabetically in the constants.ts file
• There's a lot of logic in the addLiquidity.ts, some of which is not easy to understand at first blush. We should group the code and and add annotations.

I will handle these myself.

[PaulRBerg]

Further issues:

• The comparison between the big numbers is done with the >= operator. This is, as far as I know, prone to errors. We should instead use the gt, gte, lt and lte functions shipped with @ethersproject/bignumber.
• In a similar vein, multiplication is done via the vanilla * JavaScript operator. When working with big numbers, we should always use the mul function shipped with the BigNumber class.
• Continuous integration is failing, because the lint step is failing. Issue is that there are some unused variables.
• The hTokenRatio is unnecessary, and at any rate doesn't map onto the existing naming system. We call the "ratio" a "scalar".

[PaulRBerg]

And another big big issue:

The task is calling the HifiProxyTarget, though that is supposed to be called only via the DSProxy.