Move primitives and runtime out of src/common/

Relocate src/common/primitives and src/common/runtime to src/primitives
and src/runtime. Add src/tsconfig.json as the primitives+runtime solution.
Update tsconfigs, esbuild, webpack aliases, publish path, and docs.

Co-authored-by: Daniel Imms <Tyriar@users.noreply.github.com>

src/primitives/KeyboardTypes.ts

@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) 2018 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+export interface IKeyboardEvent {
+  altKey: boolean;
+  ctrlKey: boolean;
+  shiftKey: boolean;
+  metaKey: boolean;
+  /** @deprecated See KeyboardEvent.keyCode */
+  keyCode: number;
+  key: string;
+  type: string;
+  code: string;
+}
+
+export const enum KeyboardResultType {
+  SEND_KEY,
+  SELECT_ALL,
+  PAGE_UP,
+  PAGE_DOWN
+}
+
+export interface IKeyboardResult {
+  type: KeyboardResultType;
+  cancel: boolean;
+  key: string | undefined;
+}