Implement timeout logic for potentially time unbounded tasks

We should add some timeout logic when spawning potentially time unbounded goroutines that call code we don’t directly control (e.g. a dependency). For example, this is the case of the file attachment content extraction. These goroutines can take a long time to return (or even fail to do so) causing both a leak and a potential deadlock when shutting down the server.

See https://github.com/mattermost/mattermost/pull/25227 for more context and a real world issue.

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JIRA: https://mattermost.atlassian.net/browse/MM-55260