Dialog draggable and resizable

[stevetsanders]

Is your feature request related to a problem? Please describe.
I want to be able to drag and resize a dialog.

Describe the solution you'd like
When my mouse is hovering over one of the corners of the dialog, I would like my mouse icon to change and indicate that I can resize the dialog. Once I click and drag the corner, I want the dialog to resize.

When my mouse is hovering over the header of the dialog, I would like my mouse icon to change and indicate that I can drag the dialog. Once I click and drag with my mouse, I want the dialog to move along with it.

Describe alternatives you've considered

Additional context
I believe this is already available functionality in the standard UI5 library. In order to achieve more feature parity, I think this would be an important step.

[ilhan007]

Stories

(1) As a user, I would like to be able to resize the ui5-dialog by dragging the dialog bottom-right edge

API changes

• New property "resizable": Defines whether the Dialog is resizable. If this property is set to true, the Dialog will have a resize handler in its bottom right corner.

Important: we enabled users to set dialog width and height via CSS (<ui5-dialog style="width: 100px; height:200px"), which contradicts with resizing in principle, that's why we should document that when "resizing" is enabled, the external width and height styling will be ignored.

(2) As a user, I would like to be able to drag the ui5-dialog and drop it later on by using the dialog header.

API changes

• New property "draggable": Defines whether the Dialog is draggable by its header.
  Note: This property has a default value false. The Dialog can be draggable only in desktop mode.

General info

The interaction design should be the same as in classic UI5.
See https://openui5.hana.ondemand.com/entity/sap.m.Dialog/sample/sap.m.sample.Dialog

Assignment info

The item will be planned in Team Rodopi with Medium priority. It can be easily implemented as two separate issues.

[ilhan007]

Tasks:

• draggabe feat(ui5-dialog): introduce draggable property #2269
• resizable feat(ui5-dialog): introduce resizable property #2301