Website detect logout status

[linux4life798]

The login page should be presented (with auto-redirect) when your login token has expired and you are trying to access some resource. Currently, an error is just displayed and you have to find some way to get to the main page to login.

Two problem scenarios where this occurs:

1. When your cookie has expired and you try to refresh the page on a device. An annoying error is displayed and there is no easy way to re-login.
2. When you click a link to a device and your current web browser is not logged in. The same annoying error is shown without a way to login.

[hi-liang]

Currently the redirects to home on each component (device, location, etc) are one-off error handlers based on subscription response of their respective getter requests (e.g. getDevice()).
Example:

website/src/app/components/devices/device.component.ts

Line 102 in 51243f4

error => this.router.navigate(['/home'])

This should be handled at a much lower level. Unfortunately each of the services have (copies of) their own error handlers, e.g.

website/src/app/services/device.service.ts

Line 229 in 51243f4

private handleError (error: Response | any) {

TLDR: All of this should be refactored so at lowest level possible a 401 error response leads to popup of the login component.