CLN: remove deprecated device references

[klauer]

Description

• Removed deprecated happi.containers.Device container.
• Removed deprecated methods:
  • happi.Client.create_device
  • happi.Client.add_device
  • happi.Client.find_device
  • happi.Client.all_devices
  • happi.Client.remove_device
  • happi.SearchResult.device

Motivation and Context

• v1.14.0 is tagged
• v2.0.0 is on the radar

How Has This Been Tested?

Test suite

Where Has This Been Documented?

Issues + release notes

Pre-merge checklist

• [x] Code works interactively
• [x] Code contains descriptive docstrings, including context and API
• [x] New/changed functions and methods are covered in the test suite where possible
• [x] Test suite passes locally
• [x] Test suite passes on continuous integration (Travis CI)
• [x] Ran docs/pre-release-notes.sh and created a pre-release documentation page
• [x] Pre-release docs include context, functional descriptions, and contributors as appropriate

[ZLLentz]

Any objections to me merging this?

[klauer]

🦗