[Feature] Add 'Generate' option for the data-mapping

[ArnaudB88]

In our company, we use your generator for many years now with many developers. Over the years, we added some features so it works better with our solutions. As a sign of appreciation, I want to suggest some features because I think it will help some other developers as well.

Feature description:
Add a 'generate' option for the mapping classes which indicates if the mappings should be generated or not.

YAML usage:

data:
  mapping:
    generate: true

Please review the feature request and evaluate if you think this is an addition to your repo.
(pull request will be added)

Thanks

[pwelter34]

Why would you want to turn this off? The mapping is mostly required. Are you using attribute based mapping?

[ArnaudB88]

I can assume a dev generates an initial version of the entities and de mappings, afterwards makes changes to the mapping and wants to prevent these changes to be overridden when regenerating.

[pwelter34]

you can make changes anywhere outside the region, and it will be saved.

    public void Configure(Microsoft.EntityFrameworkCore.Metadata.Builders.EntityTypeBuilder<Core.Data.Entities.Company> builder)
    {
        #region Generated Configure
        // table
        builder.ToTable("Company", "dbo");

        // key
        builder.HasKey(t => t.Id);

        // properties
        builder.Property(t => t.Id)
            .IsRequired()
            .HasColumnName("Id")
            .HasColumnType("int")
            .ValueGeneratedOnAdd();

        builder.Property(t => t.Name)
            .IsRequired()
            .HasColumnName("Name")
            .HasColumnType("nvarchar(100)")
            .HasMaxLength(100);

        #endregion
		
        // Safe to make changes here
    }

[ArnaudB88]

@pwelter34 if changes outside the generated region override the config above, it is indeed a solution.
If you think there is no other valid scenario to ignore the mappings, you can close the issue.