Change Properties to a map

[theunrepentantgeek]

What this PR does / why we need it:

Changes the Properties() method exposed by ObjectType and ResourceType to return a (strongly typed) map instead of a slice.

Most of the consumers of the method don't care about the ordering, but they're paying the price of sorting.

Introducing the type PropertySet allows for easy conversion to a slice for the few consumers that care (by calling AsSlice(), while allowing random access for other consumers.

Note that this changes the order of propeties returned from ResourceType - they're now alphabetical (Spec/Status) instead of hard coded (Status/Spec); this has resulted in minor changes to a few golden files.

Special notes for your reviewer:

The Properties() method is called a lot of times (67 references) and I haven't exahustively reviewed all of them. Instead, I've relied on the compiler, linter, and our tests, to find cases where updates are needed.

How does this PR make you feel:

If applicable:

• this PR contains tests

[codecov-commenter]

Codecov Report

Merging #1655 (e92d643) into master (02973a1) will increase coverage by 0.56%.
The diff coverage is 74.62%.

@@            Coverage Diff             @@
##           master    #1655      +/-   ##
==========================================
+ Coverage   67.08%   67.65%   +0.56%     
==========================================
  Files         205      211       +6     
  Lines       14840    15179     +339     
==========================================
+ Hits         9956    10269     +313     
- Misses       4126     4146      +20     
- Partials      758      764       +6     

Impacted Files	Coverage Δ
hack/generator/cmd/gen_kustomize.go	0.00% <0.00%> (ø)
hack/generator/cmd/gen_types.go	0.00% <0.00%> (ø)
hack/generator/cmd/root.go	0.00% <0.00%> (ø)
.../generator/pkg/astmodel/code_generation_context.go	46.87% <0.00%> (ø)
...erator/pkg/astmodel/conversion_function_builder.go	69.10% <0.00%> (-0.45%)	⬇️
hack/generator/pkg/astmodel/file_definition.go	91.53% <0.00%> (ø)
hack/generator/pkg/astmodel/package_definition.go	30.00% <0.00%> (ø)
hack/generator/pkg/astmodel/package_import.go	89.47% <0.00%> (ø)
hack/generator/pkg/astmodel/property_container.go	75.00% <ø> (ø)
...ack/generator/pkg/astmodel/test_file_definition.go	0.00% <0.00%> (ø)
... and 76 more

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