Change the internal configuration format to json and add deprecated version warning

[LavenderQAQ]

What type of PR is this?

/kind enhancement
/sig iot

What this PR does / why we need it:

• Change the internal configuration format of edgex version to json

Because the internal format of k8s uses json, we couldn't get rid of empty fields when storing yaml, which resulted in a very large configuration file. Using json as our internal storage format saves space and improves readability by removing redundant fields when exporting the configuration for the user. Of course, we need to add a layer of json-to-yaml conversion when exporting our custom configuration for the user.

• Add deprecated version warning

@Rui-Gan has completed the conversion mechanism between v1alpha1 and v1alpha2, this pr just adds a warning flag.

• Bump cicd workflow environment to ubuntu-latest

ci.yaml and release.yaml didn't work because github cicd no longer supports ubuntu-18.04, I upgraded both to ubuntu-latest

Which issue(s) this PR fixes:

Fixes #68

Special notes for your reviewer:

Does this PR introduce a user-facing change?

EdgeX v1alpha1 will be deprecated in the future.

other Note

[codecov]

Codecov Report

Merging #94 (7101bd1) into main (bd3192c) will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main      #94      +/-   ##
==========================================
+ Coverage   16.51%   16.55%   +0.03%     
==========================================
  Files           2        2              
  Lines         454      453       -1     
==========================================
  Hits           75       75              
+ Misses        373      372       -1     
  Partials        6        6              

Impacted Files	Coverage Δ
controllers/edgex_controller.go	4.65% <ø> (+0.01%)	⬆️

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[lwmqwer]

/lgtm