Feature/add all flags setting

[mlund01]

Problem
We have over 100 feature flags that we use within our app, and it's challenging to maintain a list of default values in the flags object that gets passed to the init method when the majority of them don't need to have a preset and can wait until the LD server returns with actual flag values.

Solution
This MR adds the ability to get all flags by setting allFlags: true in the new settings object param for the init method. i.e.

const flags = {'test-one': true, 'test-two': false}
ldRedux.init({
  clientSideId: 'your-client-side-id',
  dispatch: store.dispatch,
  flags,
  settings: {allFlags: true},
});

This feature can be used in combination with the flags object, but is no longer necessary if the allFlags option is set. An example without flags,

ldRedux.init({
  clientSideId: 'your-client-side-id',
  dispatch: store.dispatch,
  settings: {allFlags: true},
});

[yusinto]

Hi @mlund01 I hope you don't mind I created a new release based on your requirements, which will achieve what you want. Basically the flags argument is now optional and will default to all flags when not specified. Check out the release here. Thanks for the pr!

[mlund01]

@yusinto your changes certainly make it more flexible in a concise way. However, it would be nice to be able to pass both the flags argument and be able to get all flags. The reason for this is because some of our flags are easier to work with if there is a default value (typically the flags that get evaluated early in the load cycle when LD may not yet be loaded). I'll leave it up to you since we can work around since ld-redux-components allow you to wait for ld to be loaded and set default variants on flag components, but that's my two cents.