(core) Remove a bunch of dead code

Summary: Removed test/aws/, most of app/server/lib/, 3 dirs in app/lambda/, corresponding tests, and more!

Test Plan: a lot of this is quite the opposite...

Reviewers: dsagal, paulfitz

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2894

app/common/ActiveDocAPI.ts

@@ -1,7 +1,6 @@
 import {ActionGroup} from 'app/common/ActionGroup';
 import {CellValue, TableDataAction, UserAction} from 'app/common/DocActions';
 import {FormulaProperties} from 'app/common/GranularAccessClause';
-import {Peer} from 'app/common/sharing';
 import {UploadResult} from 'app/common/uploads';
 import {ParseOptions} from 'app/plugin/FileParserAPI';
 import {IMessage} from 'grain-rpc';
@@ -179,11 +178,6 @@ export interface ActiveDocAPI {
    */
   autocomplete(txt: string, tableId: string): Promise<string[]>;
 
-  /**
-   * Shares the doc and invites peers.
-   */
-  shareDoc(peers: Peer[]): Promise<void>;
-
   /**
    * Removes the current instance from the doc.
    */