Add code element type fields

[Fweddi]

What does this change?

See #36, #2586 and #2596.

Adds the 'code element type' to the capi model, along with html and language type fields.

This is ultimately to allow blocks of code to work in our developer blogs (previously these have been handled by html injection rather than content modelling).

How to test

I think we need to deploy a full pipeline from flex to concierge, including the models, and test the behaviour. But I need a second opinion on this.

[Fweddi]

I worry there is a conflict between the work here and the work on Concierge. There is a confusing difference between typeData (defined on the Asset struct, itself defined on the Element Struct) and codeTypeData (defined on the BlockElement struct). The code element type does not have any assets. Does this mean we don't need a typeData field, and potentially don't need to add a CodeElementGenerator at all?

[mchv]

@Fweddi I think you are mixing two things:

• show-blocks which will show code and need changes from this PR
• show-elements which will triggers CodeElementGenerator and related code. We may not need codeTypeData in elements, and I will sip without first.

[Fweddi]

@Fweddi I think you are mixing two things:

• show-blocks which will show code and need changes from this PR
• show-elements which will triggers CodeElementGenerator and related code. We may not need codeTypeData in elements, and I will sip without first.

Thanks Mariot - this cleared up things a lot!