(core) Forms feature

Summary:
A new widget type Forms. For now hidden behind GRIST_EXPERIMENTAL_PLUGINS().
This diff contains all the core moving parts as a serves as a base to extend this functionality
further.

Test Plan: New test added

Reviewers: georgegevoian

Reviewed By: georgegevoian

Subscribers: paulfitz

Differential Revision: https://phab.getgrist.com/D4130

app/client/ui2018/cssVars.ts

@@ -56,10 +56,10 @@ export const colors = {
   darkBg: new CustomProp('color-dark-bg', '#262633'),
   slate: new CustomProp('color-slate', '#929299'),
 
+  lighterGreen: new CustomProp('color-lighter-green', '#b1ffe2'),
   lightGreen: new CustomProp('color-light-green', '#16B378'),
   darkGreen: new CustomProp('color-dark-green', '#009058'),
   darkerGreen: new CustomProp('color-darker-green', '#007548'),
-  lighterGreen: new CustomProp('color-lighter-green', '#b1ffe2'),
 
   lighterBlue: new CustomProp('color-lighter-blue', '#87b2f9'),
   lightBlue: new CustomProp('color-light-blue', '#3B82F6'),

app/client/ui2018/menus.ts

@@ -1,4 +1,4 @@
-import { Command } from 'app/client/components/commands';
+import { MenuCommand } from 'app/client/components/commandList';
 import { FocusLayer } from 'app/client/lib/FocusLayer';
 import { makeT } from 'app/client/lib/localization';
 import { NeedUpgradeError, reportError } from 'app/client/models/errors';
@@ -575,7 +575,7 @@ export const menuItemAsync: typeof weasel.menuItem = function(action, ...args) {
 };
 
 export function menuItemCmd(
-  cmd: Command,
+  cmd: MenuCommand,
   label: string | (() => DomContents),
   ...args: DomElementArg[]
 ) {
@@ -787,8 +787,9 @@ const cssUpgradeTextButton = styled(textButton, `
 
 const cssMenuItemSubmenu = styled('div', `
   position: relative;
+  justify-content: flex-start;
   color: ${theme.menuItemFg};
-  --icon-color: ${theme.menuItemFg};
+  --icon-color: ${theme.accentIcon};
   .${weasel.cssMenuItem.className}-sel {
     color: ${theme.menuItemSelectedFg};
     --icon-color: ${theme.menuItemSelectedFg};