OutOfBand events not exposed properly

[morrieinmaas]

OutOfBandEvents are not exposed correctly.

For instance, one can import ConnectionStateChangedEvent from @aries-fromework/core whereas OutOfBandStateChangedEvent needs to be imported via import type { OutOfBandStateChangedEvent } from '@aries-framework/core/build/modules/oob/domain/OutOfBandEvents'. Additionally, this is annoying because the language server doesn't pick this up for autocompletion.

OUTCOME:
OutOfBandStateChangedEvent can be imported via import type {OutOfBandStateChangedEvent} from '@aries-framework/core'

Will submit fix myself. Issue just for doc purpose and have PR against it.