feat(ui5-wizard): initial implementation

[ilhan007]

Introduce ui5-wizard and ui5-wizard-step components that enables users to accomplish a single goal that consists of multiple dependable sub-tasks.

<ui5-wizard>
    <ui5-wizard-step icon="sap-icon://product" text="Product type" selected>
            <h1>Product Type</h1>
    </ui5-wizard-step>

    <ui5-wizard-step icon="sap-icon://information" text="Product Info" disabled>
             <h1>Product Info</h1>
    </ui5-wizard-step>

    <ui5-wizard-step icon="sap-icon://settings" text="Options" disabled>
             <h1>Product Options</h1>
    </ui5-wizard-step>

    <ui5-wizard-step icon="sap-icon://lead" text="Pricing" disabled>
             <h1>Product Pricing</h1>
    </ui5-wizard-step>
</ui5-wizard>

Overview
The ui5-wizard-step API defines both the content of particular step and its corresponding tab, displayed within the Wizard's navigation header with the icon and text properties. Also, the component provides selected and disabled properties, that determine which step is currently "selected" (active), which ones are enabled or disabled.
The Wizard does not provide "move to next button", instead we give the user freedom to decide how to move to particular step. It might be button, or something else, placed inside the content of step. At the end, to move to particular step, the user can use the API of the ui5-wizard-step (selected and disabled).
In terms of user experience, the wizard allows navigation between enabled (validated) steps upon clicking the steps within the navigation header and via scrolling. When these interactions occur, the wizard updates the selected state and fires selection-change event to notify the interested parties.

What is not in the initial scope:

• The "stacking" of steps in the Wizard's navigation header on small sizes. Instead, the component would hide the text and the steps' separators to free up as much space as possible.

Preview

FIXES: #2368

[vladitasev]

Looks great!

Overall I've found just very small things.

• check if tag names are used somewhere else (I only found one usage) to not break scoping
• I'm not sure whether we should automatically select the first step, but let's give it a try. We can change this later

[hrstoyanov]

when is this wizard component going to be released? Also is it possible to determine the steps dynamically (rather than have them asa fixed static sequence), based on what the user selected in previous steps. Example:

• a User registers to web site
• depending on the role s/he registers , a payment screen step is presented (or not)

[hristop]

This is an update to let you know that we have introduced a change to the naming of the wizard event 'selection-change'.

We have decided to rename the "selection-change" event in order for its name to better represent its origins.
The “selection-change” event has been renamed to "step-change". In addition, the event param "selectedStep" has been renamed to "step" and the event param "previouslySelectedStep" has been renamed to "previousStep".