feat: add global settings for teams (#1391)

## Description

This PR introduces global settings for teams. At the moment, it allows
team admins to configure the following:
* The default visibility of the documents uploaded to the team account
* Whether to include the document owner (sender) details when sending
emails to the recipients.

### Include Sender Details

If the Sender Details setting is enabled, the emails sent by the team
will include the sender's name:

> "Example User" on behalf of "Example Team" has invited you to sign
"document.pdf"

Otherwise, the email will say:

> "Example Team" has invited you to sign "document.pdf"

### Default Document Visibility

This new option allows users to set the default visibility for the
documents uploaded to the team account. It can have the following
values:
* Everyone
* Manager and above
* Admins only

If the default document visibility isn't set, the document will be set
to the role of the user who created the document:
* If a user with the "User" role creates a document, the document's
visibility is set to "Everyone".
* Manager role -> "Manager and above"
* Admin role -> "Admins only"

Otherwise, if there is a default document visibility value, it uses that
value.

#### Gotcha

To avoid issues, the `document owner` and the `recipient` can access the
document irrespective of their role. For example:
* If a team member with the role "Member" uploads a document and the
default document visibility is "Admins", only the document owner and
admins can access the document.
  * Similar to the other scenarios.

* If an admin uploads a document and the default document visibility is
"Admins", the recipient can access the document.

* The admins have access to all the documents.
* Managers have access to documents with the visibility set to
"Everyone" and "Manager and above"
* Members have access only to the documents with the visibility set to
"Everyone".

## Testing Performed

Tested it locally.

packages/email/providers/branding.tsx

@@ -0,0 +1,44 @@
+'use client';
+
+import { createContext, useContext } from 'react';
+
+type BrandingContextValue = {
+  brandingEnabled: boolean;
+  brandingUrl: string;
+  brandingLogo: string;
+  brandingCompanyDetails: string;
+  brandingHidePoweredBy: boolean;
+};
+
+const BrandingContext = createContext<BrandingContextValue | undefined>(undefined);
+
+const defaultBrandingContextValue: BrandingContextValue = {
+  brandingEnabled: false,
+  brandingUrl: '',
+  brandingLogo: '',
+  brandingCompanyDetails: '',
+  brandingHidePoweredBy: false,
+};
+
+export const BrandingProvider = (props: {
+  branding?: BrandingContextValue;
+  children: React.ReactNode;
+}) => {
+  return (
+    <BrandingContext.Provider value={props.branding ?? defaultBrandingContextValue}>
+      {props.children}
+    </BrandingContext.Provider>
+  );
+};
+
+export const useBranding = () => {
+  const ctx = useContext(BrandingContext);
+
+  if (!ctx) {
+    throw new Error('Branding context not found');
+  }
+
+  return ctx;
+};
+
+export type BrandingSettings = BrandingContextValue;