[Security] [RememberMe] Add support for parallel requests doing remembe…

[fabpot]

Q	A
Feature PR	symfony/symfony#41175
PR author(s)	@Seldaek
Merged in	5.3-dev

[Seldaek]

To document here would be the new security -> firewalls -> x -> remember_me -> token_verifier service id that can be optionally passed to use a custom TokenVerifierInterface service with the remember me functionality, by default though the CacheTokenVerifier should be autoconfigured and work sufficiently for most use cases.

[javiereguiluz]

Ping @wouterj to ask if the use case explained by Jordi is common enough to document it in Symfony Docs or we consider it too advanced and therefore we left it undocumented. Thanks!

[javiereguiluz]

Closing in favor of #15908, a meta-issue that groups all pending security-related issues so we can easily check them.