(core) Add optional telemetry to grist-core

Summary:
Adds support for optional telemetry to grist-core.

A new environment variable, GRIST_TELEMETRY_LEVEL, controls the level of telemetry collected.

Test Plan: Server and unit tests.

Reviewers: paulfitz

Reviewed By: paulfitz

Subscribers: dsagal, anaisconce

Differential Revision: https://phab.getgrist.com/D3880

app/common/gristUrls.ts

@@ -4,6 +4,7 @@ import {EngineCode} from 'app/common/DocumentSettings';
 import {encodeQueryParams, isAffirmative} from 'app/common/gutil';
 import {LocalPlugin} from 'app/common/plugin';
 import {StringUnion} from 'app/common/StringUnion';
+import {TelemetryLevel} from 'app/common/Telemetry';
 import {UIRowId} from 'app/common/UIRowId';
 import {getGristConfig} from 'app/common/urlUtils';
 import {Document} from 'app/common/UserAPI';
@@ -627,6 +628,12 @@ export interface GristLoadConfig {
 
   // Current user locale, read from the user options;
   userLocale?: string;
+
+  // Telemetry config.
+  telemetry?: TelemetryConfig;
+
+  // The Grist deployment type (e.g. core, enterprise).
+  deploymentType?: GristDeploymentType;
 }
 
 export const Features = StringUnion(
@@ -648,6 +655,13 @@ export function getPageTitleSuffix(config?: GristLoadConfig) {
   return config?.pageTitleSuffix ?? " - Grist";
 }
 
+export interface TelemetryConfig {
+  telemetryLevel: TelemetryLevel;
+}
+
+export const GristDeploymentTypes = StringUnion('saas', 'core', 'enterprise', 'electron', 'static');
+export type GristDeploymentType = typeof GristDeploymentTypes.type;
+
 /**
  * For a packaged version of Grist that requires activation, this
  * summarizes the current state. Not applicable to grist-core.