Split up render methods in assistant and builders

[cnatis]

When trying to extend the assistants/builders I find I have to copy a large code block over and only end up changing a small portion of the code. This is because the render methods are all encompassing, I have been overriding the render methods to render special values, but for the most part the rest of the assistant code is good. I'd like to have these split up a bit more so that if I only need to change the way an option is rendered in the assistant list, I could just override the relevant method.

Some examples that might be a good idea to make extending easier
Assistants

1. Render archive item
2. Render suggestion item

Builders

1. Render single readonly
2. Render multi readonly

[Ghnuberath]

This is related to #109