(core) Implement new representation of ACL rules.

Summary:
- Added fields to _grist_ACLRules for the new Granular ACL representation
- Include a corresponding migration.

- Added ACLPermissions module with merging PermissionSets and converting to/from string.
- Implemented parsing of ACL formulas and compiling them into JS functions.
- Add automatic parsing of ACL formulas when ACLRules are added or updated.
- Convert GranularAccess to load and interpret new-style rules.
- Convert ACL UI to load and save new-style rules.

For now, no attempt to do anything better on the server or UI side, only to
reproduce previous behavior.

Test Plan: Added unittests for new files; fixed those for existing files.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2664

app/common/schema.ts

@@ -1,4 +1,4 @@
-/*** THIS FILE IS AUTO-GENERATED BY sandbox/gen_js_schema.py ***/
+/*** THIS FILE IS AUTO-GENERATED BY core/sandbox/gen_js_schema.py ***/
 // tslint:disable:object-literal-key-quotes
 
 export const schema = {
@@ -146,6 +146,10 @@ export const schema = {
     principals          : "Text",
     aclFormula          : "Text",
     aclColumn           : "Ref:_grist_Tables_column",
+    aclFormulaParsed    : "Text",
+    permissionsText     : "Text",
+    rulePos             : "PositionNumber",
+    userAttributes      : "Text",
   },
 
   "_grist_ACLResources": {
@@ -313,6 +317,10 @@ export interface SchemaTypes {
     principals: string;
     aclFormula: string;
     aclColumn: number;
+    aclFormulaParsed: string;
+    permissionsText: string;
+    rulePos: number;
+    userAttributes: string;
   };
 
   "_grist_ACLResources": {