🔥 remove unused gh-spin-button component

closes https://github.com/TryGhost/Ghost/issues/7865
- `gh-spin-button` has been replaced with `gh-task-button`

ghost/admin/app/components/gh-spin-button.js

@@ -1,64 +0,0 @@
-import Component from 'ember-component';
-import Ember from 'ember';
-import {equal} from 'ember-computed';
-import observer from 'ember-metal/observer';
-import run from 'ember-runloop';
-
-// ember-cli-shims doesn't export Ember.Testing
-const {testing} = Ember;
-
-export default Component.extend({
-    tagName: 'button',
-    buttonText: '',
-    submitting: false,
-    showSpinner: false,
-    showSpinnerTimeout: null,
-    autoWidth: true,
-
-    // Disable Button when isLoading equals true
-    attributeBindings: ['disabled', 'type', 'tabindex'],
-
-    // Must be set on the controller
-    disabled: equal('showSpinner', true),
-
-    click() {
-        if (this.get('action')) {
-            this.sendAction('action');
-            return false;
-        }
-        return true;
-    },
-
-    toggleSpinner: observer('submitting', function () {
-        let submitting = this.get('submitting');
-        let timeout = this.get('showSpinnerTimeout');
-        let delay = testing ? 10 : 1000;
-
-        if (submitting) {
-            this.set('showSpinner', true);
-            this.set('showSpinnerTimeout', run.later(this, function () {
-                if (!this.get('submitting')) {
-                    this.set('showSpinner', false);
-                }
-                this.set('showSpinnerTimeout', null);
-            }, delay));
-        } else if (!submitting && timeout === null) {
-            this.set('showSpinner', false);
-        }
-    }),
-
-    setSize: observer('showSpinner', function () {
-        if (this.get('showSpinner') && this.get('autoWidth')) {
-            this.$().width(this.$().width());
-            this.$().height(this.$().height());
-        } else {
-            this.$().width('');
-            this.$().height('');
-        }
-    }),
-
-    willDestroy() {
-        this._super(...arguments);
-        run.cancel(this.get('showSpinnerTimeout'));
-    }
-});

ghost/admin/app/styles/patterns/buttons.css

@@ -317,54 +317,6 @@ svg.gh-btn-icon-right {
 }
 
 
-/*
-/* Loading Button Spinner
-/* ---------------------------------------------------------- */
-/*
-
-Usage: Swap out button>span text with HTML
-
-<a class="gh-btn gh-btn-blue">
-    <span>
-        <div class="gh-spinner"></div>
-    </span>
-</div>
-
-*/
-
-.gh-spinner {
-    position: relative;
-    display: inline-block;
-    width: 18px;
-    height: 18px;
-    border: rgba(0,0,0,0.2) solid 4px;
-    border-radius: 100%;
-    animation: spin 1s linear infinite;
-}
-
-.gh-spinner:before {
-    content: "";
-    display: block;
-    margin-top: 9px;
-    width: 4px;
-    height: 4px;
-    background: rgba(0,0,0,0.6);
-    border-radius: 100%;
-}
-
-@keyframes spin {
-    0% {
-        transform: rotate(0deg);
-    }
-    50% {
-        transform: rotate(180deg);
-    }
-    100% {
-        transform: rotate(360deg);
-    }
-}
-
-
 /*
 /* Button Variations
 /* ---------------------------------------------------------- */

ghost/admin/app/templates/components/gh-spin-button.hbs

@@ -1,9 +0,0 @@
-{{#if showSpinner}}
-    <span>{{inline-svg "spinner"}}</span>
-{{else}}
-    {{#if buttonText}}
-        {{buttonText}}
-    {{else}}
-        {{{yield}}}
-    {{/if}}
-{{/if}}

ghost/admin/tests/unit/components/gh-spin-button-test.js

@@ -1,23 +0,0 @@
-/* jshint expr:true */
-import {expect} from 'chai';
-import {describe, it} from 'mocha';
-import {setupComponentTest} from 'ember-mocha';
-
-describe('Unit: Component: gh-spin-button', function () {
-    setupComponentTest('gh-spin-button', {
-        unit: true
-        // specify the other units that are required for this test
-        // needs: ['component:foo', 'helper:bar']
-    });
-
-    it('renders', function () {
-        // creates the component instance
-        let component = this.subject();
-
-        expect(component._state).to.equal('preRender');
-
-        // renders the component on the page
-        this.render();
-        expect(component._state).to.equal('inDOM');
-    });
-});