added welcome tab (fixes #845)

terminus-core/src/components/welcomeTab.component.pug

@@ -0,0 +1,19 @@
+.mb-4
+    .terminus-logo
+    h1.terminus-title Terminus
+        sup α 
+
+.container
+    .text-center.mb-5 Thank you for downloading Terminus!
+
+    .form-line
+        .header
+            .title Enable analytics
+            .description Help us track the number of Terminus installs across the world!
+        toggle(
+            [(ngModel)]='config.store.enableAnalytics',
+            (ngModelChange)='config.save(); config.requestRestart()',
+        )
+
+    .text-center.mt-5
+        button.btn.btn-primary((click)='closeAndDisable()') Close and never show again

terminus-core/src/components/welcomeTab.component.scss

@@ -0,0 +1,6 @@
+:host {
+    display: flex;
+    flex-direction: column;
+    margin: auto;
+    flex: 0 1 500px;
+}

terminus-core/src/components/welcomeTab.component.ts

@@ -0,0 +1,26 @@
+import { Component } from '@angular/core'
+import { BaseTabComponent } from './baseTab.component'
+import { ConfigService } from '../services/config.service'
+import { AppService } from '../services/app.service'
+
+/** @hidden */
+@Component({
+    selector: 'welcome-page',
+    template: require('./welcomeTab.component.pug'),
+    styles: [require('./welcomeTab.component.scss')],
+})
+export class WelcomeTabComponent extends BaseTabComponent {
+    constructor (
+        private app: AppService,
+        public config: ConfigService,
+    ) {
+        super()
+        this.setTitle('Welcome')
+    }
+
+    closeAndDisable () {
+        this.config.store.enableWelcomeTab = false
+        this.config.save()
+        this.app.closeTab(this)
+    }
+}