[EPH] use EventHubConnectionConfig and remove dependency on amp-common and rhea-promise

[amarzavery]

• Remove @azure/amqp-common and rhea-promise as dependencies, since we use very little from
  those libraries and there is a risk of having two instances of rhea in the dependency chain which
  can cause problems while encoding types for filters.
• HostContext.connectionConfig is now of type EventHubConnectionConfig.
• Minimum dependency on @azure/event-hubs: "^1.0.6".

[amarzavery]

✅ Validation status: passed

File	Status	Preview URL	Details
.travis.yml	✅Succeeded
processor/changelog.md	✅Succeeded
processor/lib/azureBlob.ts	✅Succeeded
processor/lib/blobService.ts	✅Succeeded
processor/lib/hostContext.ts	✅Succeeded
processor/lib/partitionScanner.ts	✅Succeeded
processor/lib/util/constants.ts	✅Succeeded
processor/lib/util/utils.ts	✅Succeeded
processor/package-lock.json	✅Succeeded
processor/package.json	✅Succeeded
processor/tests/eph.spec.ts	✅Succeeded
processor/tests/iothub.spec.ts	✅Succeeded
processor/tests/retry.spec.ts	✅Succeeded

For more details, please refer to the build report.

Note: If you changed an existing file name or deleted a file, broken links in other files to the deleted or renamed file are listed only in the full build report.

[amarzavery]

✅ Validation status: passed

File	Status	Preview URL	Details
.travis.yml	✅Succeeded
processor/changelog.md	✅Succeeded
processor/lib/azureBlob.ts	✅Succeeded
processor/lib/blobService.ts	✅Succeeded
processor/lib/hostContext.ts	✅Succeeded
processor/lib/partitionScanner.ts	✅Succeeded
processor/lib/util/constants.ts	✅Succeeded
processor/lib/util/utils.ts	✅Succeeded
processor/package-lock.json	✅Succeeded
processor/package.json	✅Succeeded
processor/tests/eph.spec.ts	✅Succeeded
processor/tests/iothub.spec.ts	✅Succeeded
processor/tests/retry.spec.ts	✅Succeeded

For more details, please refer to the build report.

Note: If you changed an existing file name or deleted a file, broken links in other files to the deleted or renamed file are listed only in the full build report.