ENH: happi config cli sub-commands

[untzag]

Description

Adding new sub-command-group config to CLI.

• happi config edit - open config file in $EDITOR
• happi config init - create new config file with default options
• happi config show - show location & contents of config file

Motivation and Context

See #314

How Has This Been Tested?

Tested on my machine.

Where Has This Been Documented?

CLI is auto-documented.

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 GitHub Actions
• [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

[tangkong]

Whoops, the failures from the test suite are coming from the way I assumed the context would be loaded. Sorry, I didn't realize this refactor would be so involved. The change needed is pretty quick though: Also use the happi_cfg fixture and pass that in as the obj in any cli test.

An Example:

def test_search(client: happi.client.Client, happi_cfg: str):
    res = client.search_regex(beamline="TST")

    with search.make_context('search', ['beamline=TST'], obj=happi_cfg) as ctx:
        res_cli = search.invoke(ctx)

    assert [r.item for r in res] == [r.item for r in res_cli]

I can push some changes real quick