Remove exposure of PropertiesCommand

[fdiaz]

The properties command is not being used externally at the moment and it's implementation doesn't fully follow the patterns we've been using recently.

I've been refactoring the PropertySyntaxVisitor to conform to these patterns but while doing so I discovered all of these classes that are currently unused, so let's get rid of them to make cleaning up and evloving PropertySyntaxVisitor easier.

[codecov]

Codecov Report

Merging #98 (a3035cd) into main (a0aae5f) will decrease coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #98      +/-   ##
==========================================
- Coverage   99.21%   99.16%   -0.06%     
==========================================
  Files          39       36       -3     
  Lines        1280     1195      -85     
==========================================
- Hits         1270     1185      -85     
  Misses         10       10              

Impacted Files	Coverage Δ
...rces/SwiftInspectorCommands/InspectorCommand.swift	100.00% <ø> (ø)
...SwiftInspectorVisitors/PropertySyntaxVisitor.swift	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a0aae5f...a3035cd. Read the comment docs.