Implement stark key registration

[torztomasz]

Resolves L2B-798, L2B-1303, L2B-1302

[linear]

L2B-798 Implement stark key registration

Doing this right is actually quite tricky, because what you need to do varies depending on what system you are using and we only know the correct steps for dYdX and dYdX doesn't need registration.

Registration is a multi step process:

1. The user logs in and clicks on their profile button in the top right
2. Because we don't know their stark key we display a page that says that they should register. This is actually not the user page, it just sorta looks similar.
3. User clicks register and signs one or more messages. Using those we derive a stark key and all necessary details for the registration transaction.
4. We show the user their stark key and their user page with both their stark key and ethereum address. Unfortunately since they aren't registered yet they cannot send forced transactions. We shouldn't display any buttons on asset list, even though it is their user page.
5. The user can click register and they are prompted to send a registration transaction via metamask. Once the registration completes we show the regular user page.

To help with implementing this the "hard part" is already done:

• the packages/frontend/src/scripts/keys/recovery.ts file includes functions to sign messages and derive keys for step 3
• the Wallet.sendRegistrationTransaction function can be used to complete step 5

The missing parts are:

• remembering the result of recoverKeysDydx, recoverKeysDydxLegacy or any future recoverKeys function to local storage
• choosing the correct recover… function based on which system we are using. I imagine we're going to have recoverKeysMyria and recoverKeysGammaX but because we don't know what the specifics are for those systems we do not have those functions. This should be flexible so that it's easy to add new ones.
• passing the values read from local storage to Wallet.sendRegistrationTransaction
• when user logs in using an account for which we remembered a stark key we need to set an appropriate cookie. Similarly when they change account / log out we need to unset the cookie
• all visuals

Currently there is no transaction page planned for registration.

[linear]

L2B-1303 Remove signature from local storage when disconnecting user (metamask)

L2B-1302 remove starkKey cookie when metamask is disconnected