Introduce vaadin-style side menu and legacy links to the angular app [~8-13]

[MartinWahnschaffe]

Problem Description

The angular app currently comes with a top menu, while the Vaadin "legacy" app uses a side menu.
To allow for a seamless switch between both apps, the angular app should come with a side menu that looks the same as the menu of the Vaadin app.

Proposed Change

• Replace the top menu with a side menu that looks like the vaadin app's menu
• Should be easy to adjust in code wheter a menu entry links to the angular app or the vaadin legacy app

Added Value/Benefit

See #11666

Acceptance Criteria

• The menu looks like the vaadin app's menu
• When connected to a legacy app, all menu entries that are not angular exclusive, link to the legacy app
• It's still possible to "manually" open any angular app view, using the URL

Implementation Details

• Add a new side menu component that is used by default. The old menu should stay available in the code, but not be used for now.
• Style the menu to look like the Vaadin menu, including the SORMAS logo
• Add all menu entries in the same order as in the Vaadin app
• Define vaadin UI "legacy" paths for all menu entries
• Add an environment config that defines the host address of the vaadin app. If defined, all menu entries that have a legacy path should link to the legacy app instead of the angular app

Mockups

No response

Additional Information

• Use keycloak login with the apps. See:
  https://github.com/hzi-braunschweig/SORMAS-Project/blob/development/docs/SERVER_SETUP.md#keycloak-as-a-docker-container and
  https://github.com/hzi-braunschweig/SORMAS-Angular/blob/development/docs/auth-keycloak.md

Out of scope

• Considering active feature types and user rights to decide which menu entries should be visible will be done in a separate issue.

[MartinWahnschaffe]

I have created a draft here: SORMAS-Foundation/SORMAS-Angular#511

• Comes with basic side-menu that is not styled yet
• Logic for legacy url is working
• Feature configuration is not considered yet