Mullvad Browser strings

This commit adds strings needed by the following Mullvad Browser
patches.

toolkit/locales/en-US/toolkit/global/mullvad-browser.ftl

+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+## About Mullvad browser dialog.
+
+mullvad-about-desc = { -brand-short-name }  is a privacy-focused web browser developed in collaboration between <label data-l10n-name="mullvad-about-mullvadLink">Mullvad VPN</label> and the <label data-l10n-name="mullvad-about-torProjectLink">Tor Project</label>. It’s produced to minimize tracking and fingerprinting.
+mullvad-about-readMore = Read more
+# Variables
+#   $emailAddress (String) - The email address of Mullvad's support
+mullvad-about-feedback2 = Help & feedback: { $emailAddress }
+mullvad-about-telemetryLink = Telemetry
+
+## Mullvad browser home page.
+
+about-mullvad-browser-heading = { -brand-product-name }
+about-mullvad-browser-developed-by = Developed in collaboration between the <a data-l10n-name="tor-project-link">Tor Project</a> and <a data-l10n-name="mullvad-vpn-link">Mullvad VPN</a>
+about-mullvad-browser-use-vpn = Get more privacy by using the browser <a data-l10n-name="with-vpn-link">with Mullvad VPN</a>.
+about-mullvad-browser-learn-more = Curious to learn more about the browser? <a data-l10n-name="learn-more-link">Take a dive into the mole hole</a>.
+
+# Update message.
+# <a data-l10n-name="update-link"> should contain the link text and close with </a>.
+# $version (String) - The new browser version.
+about-mullvad-browser-update-message =  { -brand-short-name } has been updated to { $version }. <a data-l10n-name="update-link">See what’s new</a>
+
+## Home preferences.
+
+home-mode-choice-mullvad =
+    .label = { -brand-product-name } Home
+
+## about:rights page.
+
+rights-mullvad-intro = { -brand-short-name } is free and open source software.
+rights-mullvad-you-should-know = There are a few things you should know:
+rights-mullvad-trademarks =
+    You are not granted any trademark rights or licenses to the trademarks of
+    the { -brand-short-name } or any party, including without limitation the
+    { -brand-short-name } name or logo.
+
+## about:telemetry page.
+
+telemetry-title = Telemetry Information
+telemetry-description = Telemetry is disabled in { -brand-short-name }.