#5569 Feat/update ftx spot connector

Upgrade of FTX spot connector to the latest standards. The connector has been transformed in a pure Python connector, and is now a subclass of ExchangePyBase. All unit tests for it have been implemented.

The PR also includes a change to remove the reference to the configuration map from the AsyncThrottler, that was causing issues during tests runs because the whole Hummingbot connectors configuration was being loaded (and hence the PairFetcher was executed) It also includes an improvement in the logic that generates client order ids, to reduce the possibility of having repeated ids in different bot instances using the same API keys and trading the same pairs.

PR: https://github.com/hummingbot/hummingbot/pull/5569