fix(docs): Omit AsyncStorage from basic ReactotronConfig.js

[carmeli-tamir]

Please verify the following:

• [X ] yarn build-and-test:local passes
• [X ] I have added tests for any new features, if relevant
• [X ] README.md (or relevant documentation) has been updated with your changes

Describe your PR

Without AsyncStorage dependency, the instruction in "Step 2 - Initialization" simply doesn´t work if the developer app doesn´t already use AsyncStorage, since it does ´Reactotron.setAsyncStorageHandler(AsyncStorage)´

Since AsyncStorage isn´t required for the base configuration, remove it.

[morganick]

@joshuayoes anything else we want to do here?