Dialog JS API

[joepavitt]

Closes #830

JS API
Includes additional JS api to open Dialogs. I've overridden the initial dialogs where appropriate, mostly in "Delete" use cases, e.g.:

Dialog.show({
        header: '<header title>',
        kind: (optional) 'danger',
        text: 'show this message in the dialog',
        html: 'instead of "text", you can provide html for more custom appearance and content',
        confirmLabel: '<confirm-label>'
}, async () => {
        // callback goes here
})

Architecture
The core dialog service lives in ./frontend/src/services/dialog.js. The key .show() function is used across the app in order to show and act upon confirmation of any dialogs.

The bind function is called from ./frontend/src/layouts/Platform.vue. There is an instance of ff-dialog here that is driven by the bind function. When show() is called, the dialog being modified/shown is this instance.

Testing
Given that we now have E2E testing up and running, I've also used this as an opportunity to include a bunch of E2E tests that then cover a lot of primary use cases that use these Dialogs. I haven't gone for 100% coverage on this, but it's a significant dent into a backlog of technical testing debt too.

[Steve-Mcl]

All viewed, ran locally, all good :)

[Steve-Mcl]

All issues resolved, ready to merge @joepavitt 👍