Add support for password protection to Contentful routes

[kkartunov]

If a password is set on route level in Contentful user should be presented with an auth screen to type that password then continue to content. In case the password is wrong then a simple error message in red above the button will inform the user.

[SathyaJayabal]

verified on test

[sandhiyakavi]

Verified on Staging.

[SathyaJayabal]

verified on prod