(core) copy settings related to gvisor from staging to prod

Summary:
This enables ptrace and modifies a nofile limit, to be consistent with staging. The nofile change isn't really needed, it was for gvisor's vfs2 which we are no longer using, it is just for consistency.

This diff also documents the PYTHON_VERSION_ON_CREATION=3 flag active in staging and ~~soon to be active in~~ production.

Test Plan: settings work in staging

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D3125

test/nbrowser/testServer.ts

@@ -232,6 +232,14 @@ export class TestServerMerged implements IMochaServer {
       if (origTypeormDB) {
         process.env.TYPEORM_DATABASE = origTypeormDB;
       }
+      // If this is Sqlite, we are making a separate connection to the database,
+      // so could get busy errors. We bump up our timeout. The rest of Grist could
+      // get busy errors if we do slow writes though.
+      const connection = this._dbManager.connection;
+      const sqlite = connection.driver.options.type === 'sqlite';
+      if (sqlite) {
+        await this._dbManager.connection.query('PRAGMA busy_timeout = 3000');
+      }
     }
     return this._dbManager;
   }