Develop acf-field/acf-field block

[bobbingwide]

This issue is to extract the acf-field block logic from oik-testimonials to this new plugin.

Background

• For oik-testimonials' integration with ACF I first developed a version which would use ACF's logic rather than oik-field's logic.
• I then developed shortcodes to display testimonials using fields defined using ACF.
• Next I developed an acf-cycler block.
• And then I started developing an acf-field block to display
  see Add generic ACF block to display any field oik-testimonials#7

After a while I realised that the acf-field block should be a single block plugin that didn't come with the oik-testimonials and acf-cycler baggage. So I cloned the oik-testimonials plugin to acf-field-block.

Requirements

• Develop a single block plugin to deliver an acf-field block
• The field block should be able to display any ACF field type associated with any block editor enabled post type.
• The block should be extensible, allowing other plugins or themes to provide their own rendering for a field.
• The block should provide many of the supports attributes
• Optionally the block could deliver several styles
• The plugin should be developed to WordPress coding guidelines

Proposed solution

• The oik-testimonials/acf-field block will be renamed to acf-field/acf-field
• The unrequired logic for oik-testimonials should be deleted
• The field types not yet supported at the time of cloning should be added
• Refactor the functions to use an ACF_Field class
• Add hooks to enable plugins to extend the functionality

[bobbingwide]

I'm going to close this issue now.

• There are several other issues to develop support for the different field types that I hadn't attempted.
• While trying to develop PHP Unit Tests I noticed problems with the logic to determine the list of fields to be displayed.
• One is to do with the use of the Clone field type.
• These problems will be addressed in separate issues.