(core) move home server into core

Summary: This moves enough server material into core to run a home server.  The data engine is not yet incorporated (though in manual testing it works when ported).

Test Plan: existing tests pass

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2552

app/common/sharing.ts

@@ -0,0 +1,43 @@
+import {EncActionBundleFromHub} from 'app/common/EncActionBundle';
+
+export const allToken: string = '#ALL';
+
+/**
+ * Messages received from SQS
+ */
+export interface Message {
+  type: MessageType;
+  content: Invite | EncActionBundleFromHub;
+  docId: string; // The docId to which the message pertains.
+}
+
+export enum MessageType {
+  invite = 1,
+  accept,
+  decline,
+  action
+}
+
+export interface Invite {
+  senderEmail: string;
+  senderName?: string;
+  docId: string;  // Indicates the doc to which the user is being invited to join.
+  docName: string; // Indicates the docName at the time of sending for user doc recognition.
+  isUnread?: boolean;
+  isIgnored?: boolean;
+}
+
+/**
+ * Contains information about someone who may or may not be a Grist user.
+ */
+export interface Peer {
+  email: string;
+  name?: string;
+  instIds?: string[];
+}
+
+export interface EmailResult {
+  email: string;
+  instIds: string[];
+  name?: string;
+}