[Frontend] Settings for profile fields (#1885)

* get max emoji size from instance settings

* expose (hardcoded) max amount of profile fields in instance api

* basic profile field setting

* fix profile field hook structure for updates

* *twirls mustache* fix ze tests

---------

Co-authored-by: tsmethurst <tobi.smethurst@protonmail.com>

web/source/settings/lib/form/context.jsx

@@ -0,0 +1,33 @@
+/*
+	GoToSocial
+	Copyright (C) GoToSocial Authors admin@gotosocial.org
+	SPDX-License-Identifier: AGPL-3.0-or-later
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+"use strict";
+
+const React = require("react");
+
+const FormContext = React.createContext({});
+
+module.exports = {
+	FormContext,
+	useWithFormContext(index, form) {
+		const formContainer = React.useContext(FormContext);
+		formContainer[index] = form;
+		return form;
+	}
+};