feat(map): Codegen for Go Target

[jonathan-casey]

Description

Add Go code generation for Map Type.

Sample

dictionary1 := make(map[string]string)

Author Checklist

• Ensure you provide a DCO sign-off for your commits using the --signoff option of git commit.
• Vital features and changes captured in unit and/or integration tests
• Commits messages follow AP format
• Extend the documentation, if necessary

[coveralls]

coverage: 98.949% (+0.005%) from 98.944%
when pulling cb72d75 on jonathan/codegen_map_golang
into e3111a0 on main.

[mttrbrts]

A couple of minor comments.

Please confirm that you can compile the output string.

[jonathan-casey]

@dselman the type is now retrieved from the model file.