feat(ui5-breadcrumbs): Initial implementation

[kineticjs]

Fixes #3166

Two implementations are available:

1. ui5-breadcrumbs with "current-location" property e.g.:
   <ui5-breadcrumbs current-location="Laptop"> <ui5-link>Products</ui5-link> <ui5-link>Suppliers</ui5-link> <ui5-link>Titanium</ui5-link> </ui5-breadcrumbs>
   Code: https://github.com/kineticjs/ui5-webcomponents/tree/breadcrumbs

2. ui5-breadcrumbs with links only e.g.:
   <ui5-breadcrumbs> <ui5-link>Products</ui5-link> <ui5-link>Suppliers</ui5-link> <ui5-link>Titanium</ui5-link> <ui5-link>Current</ui5-link> </ui5-breadcrumbs>
   Code: https://github.com/kineticjs/ui5-webcomponents/tree/breadcrumbs1

THIS PR IS FOR THE 2nd INPLEMENTATION (links only), because its API seemed to be preferred
However, both versions are proposed, esp. as the 1st seem better to me from performance perspective)

Note:
The 2nd implementation (links only) seemed to require some extra performance cost.
This is because the last slotted link is used to indicate the current location
=> the text of the last slotted link is rendered as ui5-label
=> I had to ensure we are notified for changes in the text of the last link
=> I had to additionally declare:
-- ui5-link declared to have managedSlots = true
-- ui5-breadcrumbs declared to invalidateOnChildChange: {
properties: false,
slots: true,
}
No such need detected for implementation 1 (with "current-location" property) as it only listens for resize of its content.

Feel free to propose improvements. I will complete the version (1 or 2) that we eventually choose.

[CLAassistant]

All committers have signed the CLA.

[kineticjs]

I'm still investigating an issue will failing tests (popovers cannot be opened on the remote server even though no issue in local executions)
but open the PR for review in order to collect early feedback regarding which implementation version (of the two described above) you find better.

[kineticjs]

The the issue with failing tests is resolved