feat(core/dropdown-button): add dropdown-button

[goncalosard]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (yarn build) was run locally and any changes were pushed
• Unit tests (yarn test) were run locally and passed
• Visual Regression Tests (yarn visual-regression) were run locally and passed
• Linting (npm lint) was run locally and passed

Pull request type

Please check the type of change your PR introduces:

• Bug fix
• Feature
• Refactoring (no functional changes, no API changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the new behavior?

Implemented new component dropdown-button as requested in #173

A new prop in icon-button was also implemented to let the small triangle to be toggle when its used on a dropdown-button.

Build is not passing because of the problem that i'm Windows, so the file component-doc.json needs to be re-commited by someone with mac.

Visual-regression tests for this new component are created, but it is needed to check if any onther tests are failing and the new
snapshots need to be commited.

Code used for testing

    <ix-dropdown-button
      label="Dropdown"
      variant="Primary"
      icon="checkboxes"
    ></ix-dropdown-button>
    <ix-dropdown-button
      label="Dropdown"
      variant="Primary"
      outline
      icon="checkboxes"
    ></ix-dropdown-button>
    <ix-dropdown-button
      label="Dropdown"
      variant="Primary"
      ghost
      icon="checkboxes"
    ></ix-dropdown-button>
    <ix-dropdown-button
      label="Dropdown"
      variant="Primary"
      disabled
      icon="checkboxes"
    ></ix-dropdown-button>
    <ix-dropdown-button
      label=""
      variant="Primary"
      icon="checkboxes"
    ></ix-dropdown-button>
    <ix-dropdown-button
      label=""
      variant="Primary"
      outline
      icon="checkboxes"
    ></ix-dropdown-button>
    <ix-dropdown-button
      label=""
      variant="Primary"
      ghost
      icon="checkboxes"
    ></ix-dropdown-button>
    <ix-dropdown-button
      label=""
      variant="Primary"
      disabled
      icon="checkboxes"
    ></ix-dropdown-button>

Testing

Tested locally

[danielleroux]

• documentation is missing
• angular (angular-test-app/preview-examples) examples are missing
• react (react-test-app/preview-examples) examples are missing
• html (html-test-app/preview-examples) examples are missing

[danielleroux]

• DropdownButton should also provide a possiblity to open a dropdown e.g.

<ix-dropdown-button>
  <ix-dropdown-item></ix-dropdown-item>
  <ix-dropdown-item></ix-dropdown-item>
  ....
</ix-dropdown-button>

See ix-select

[goncalosard]

@danielleroux
Last commit fixed the requests you made(css, triangle, dropdown). Added documentation and examples.
Triangle color is not correct, it cannot inherit, so a variable is needed to match the colors of the icons with the triangle.

[danielleroux]

@goncalosard

• Please merge with latest main the branch looks stale to me
• After merge with latest you must adapt the documentation regarding the playground component (see other docs e.g. buttons.md)
• Dropdown without icon looks broken

[goncalosard]

@goncalosard

• Please merge with latest main the branch looks stale to me
• After merge with latest you must adapt the documentation regarding the playground component (see other docs e.g. buttons.md)
• Dropdown without icon looks broken

@danielleroux

Added all the requests you made. Please check if its ok.

Build failed because component-doc.json, add your file.

[danielleroux]

lgtm

[nuke-ellington]

lgtm