Enable open enums (proof of concept)

[rpocklin]

For review

Example (before):

[JsonConverter(typeof(StringEnumConverter))]
public enum AccountType
{
    [EnumMember(Value = "BANK")]
    BANK = 0,
    
    [EnumMember(Value = "CURRENT")]
    CURRENT = 1,
    
    [EnumMember(Value = "EQUITY")]
    EQUITY = 2,
    // ...
}

Example (after):

public class AccountType {
    public string Value { get; set; }
    
    // Known constants
    public static readonly string BANK = "BANK";
    public static readonly string CURRENT = "CURRENT";
    public static readonly string EQUITY = "EQUITY";
}

[github-actions]

PETOSS-831

[github-actions]

Thanks for raising an issue, a ticket has been created to track your request

[ryanNexus]

need to merge main to this branch and fix linting please so all checks pass otherwise LTGM 😄

[rpocklin]

Closing for now - we should consider the recommended approach of defining string enums using the new approach in OAS 3.1 (see here)