feat: add language switcher (#1337)

## Description

Web changes:

- Enabled i18n for web
- Add option to change language in command menu
- Add option to change language in menu-switcher

Web and marketing changes:

- Stop setting 'en' preference into cookie if the user's language is not
supported
- Dropped middleware changes
- Rotated cookie from 'i18n' to 'language'

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
- Introduced a language switcher in the footer for improved language
selection.
	- Added dynamic language change functionality in the command menu.
- Implemented a dropdown menu item for quick access to the language
switcher.

- **Bug Fixes**
- Resolved issues related to language change notifications and state
management.

- **Translations**
- Added new translation entries for improved language support, including
"Search languages..." in English and German.
	- Updated existing translations to enhance clarity and accuracy.

- **Chores**
	- Simplified internationalization handling in middleware.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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Co-authored-by: github-actions <github-actions@documenso.com>

packages/lib/translations/de/common.po

@@ -522,6 +522,10 @@ msgstr "Speichern"
 msgid "Save Template"
 msgstr "Vorlage speichern"
 
+#: packages/ui/components/common/language-switcher-dialog.tsx:34
+msgid "Search languages..."
+msgstr "Sprachen suchen..."
+
 #: packages/ui/primitives/document-flow/field-items-advanced-settings/dropdown-field.tsx:105
 msgid "Select"
 msgstr "Auswählen"