Add ability to define what kind of keys are stored prod/staging

[ZIMkaRU]

This PR adds ability to define what kind of keys are stored prod/staging:

• The prod/staging is detected by existing the staging string in the restUrl config option: https://api-pub.bitfinex.com/https://api.staging.bitfinex.com
• and isStagingBfxApi flag is set or updated on signUp/signIn to the user table
• than, getUsers endpoint will return the isStagingBfxApi flag to be shown in the UI for each user on the login stage

---

Basic changes:

• Adds isStagingBfxApi endpoint
• Adds ability to returns isStagingBfxApi flag for signIn endpoint
• Adds ability to return isStagingBfxApi flag for getUsers endpoint
• Adds ability to set isStagingBfxApi flag on sign-up/sign-in
• Adds v39 DB migration
• Adds corresponding test coverage for isStagingBfxApi

---

isStagingBfxApi request example:

{
  "method": "isStagingBfxApi"
}

isStagingBfxApi response example:

{
    "jsonrpc": "2.0",
    "result": false,
    "id": null
}

signIn request example:

{
  "auth": {
    "email": "[email protected]",
    "isSubAccount": false
  },
  "method": "signIn"
}

signIn response example:

{
    "jsonrpc": "2.0",
    "result": {
        "email": "[email protected]",
        "isSubAccount": false,
        "token": "559cb736-ffdd-4f7d-9a53-362d913bdc16",
        "shouldNotSyncOnStartupAfterUpdate": false,
        "authTokenTTLSec": null,
        "localUsername": null,
        "lastSyncMts": 1704177514708,
        "isStagingBfxApi": false // The flag
    },
    "id": null
}

getUsers request example:

{
  "method": "getUsers"
}

getUsers response example:

{
    "jsonrpc": "2.0",
    "result": [
        {
            "email": "[email protected]",
            "localUsername": null,
            "isSubAccount": false,
            "isNotProtected": true,
            "subUsers": [],
            "isRestrictedToBeAddedToSubAccount": true,
            "isApiKeysAuth": false,
            "isStagingBfxApi": false // The flag
        },
        {
            "email": "[email protected]",
            "localUsername": null,
            "isSubAccount": false,
            "isNotProtected": true,
            "subUsers": [],
            "isRestrictedToBeAddedToSubAccount": false,
            "isApiKeysAuth": true,
            "isStagingBfxApi": true // The flag
        }
    ],
    "id": null
}

[ezewer]

looks good to me!