Single field sub form interface

Intent: Allow for easy implementation of single value (no form group) custom components that implement value accessor interface. This would allow to create smart components like selects / autocompletes that load data themselves that can easily be reused across the application Think customer / user / country pickers or any commonly used domain specific pickers you can think of.

Issue today:

• NgxSubFormComponent requires a complex type as generic parameter for class fields / methods to make sense formControlNames etc.
• Its possible to use NgxSubFormRemapComponent to wrap the single value into a form group and back but it generates boilerplate that is redundant and feels unnecessary especially for new devs joining a project

Feature request: Create an additional interface that exposes the same functionality as NgxSubFormComponent or NgxSubFormRemapComponent but all methods / fields should be singular formControlName / formControlValue etc.

UPDATE: https://stackblitz.com/edit/issue-demo-ngx-sub-form-single-value

Notes:

• checkout the GenericLookupComponent
• here you can see how the single value is wrapped / unwrapped

[ntziolis]

Will do

[ntziolis]

To better understand the use cases for single value sub forms and as mentioned in #139 we have also created an additional sub form type for arrays with array related helper functionality, sample can be found here