[IMP] web: Allow displaying simple json fields

Purpose
=======

It is currently impossible to display a json field on a form view without
defining a specific widget.

Allow displaying the json field in its simplest form, aka the stringified
content in readonly mode.

TaskID: 3101400

addons/web/static/src/views/fields/jsonb/jsonb.js

@@ -0,0 +1,26 @@
+/** @odoo-module **/
+
+import { _lt } from "@web/core/l10n/translation";
+import { registry } from "@web/core/registry";
+import { standardFieldProps } from "../standard_field_props";
+
+import { Component } from "@odoo/owl";
+
+export class JsonField extends Component {
+    static template = "web.JsonbField";
+    static props = {
+        ...standardFieldProps,
+    };
+    get formattedValue() {
+        const value = this.props.record.data[this.props.name];
+        return value ? JSON.stringify(value) : "";
+    }
+}
+
+export const jsonField = {
+    component: JsonField,
+    displayName: _lt("Json"),
+    supportedTypes: ["jsonb"],
+};
+
+registry.category("fields").add("jsonb", jsonField);

addons/web/static/src/views/fields/jsonb/jsonb.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<templates id="template" xml:space="preserve">
+
+    <t t-name="web.JsonbField" owl="1">
+        <span t-esc="formattedValue" />
+    </t>
+
+</templates>