Closes #2876.

Closes #2873.

Closes #2789. Thanks to Daedaluz.

Closes #2855. Thanks to cfi-gb

Closes #2839. Thanks to KaeLL

Closes #2867

This allows us to refuse to open an existing file, without a race
condition.

This occurs when they have a will message that contains invalid property
types.

Identified by OS-TIF audit.

TOB-MOSQ-CR-5

- Broker will log warnings if sensitive files are world readable/writable, or
  if the owner/group is not the same as the user/group the broker is running
  as. In future versions the broker will refuse to open these files.

Fix engine keyfile support.

Closes #2799. Thanks to n00b42

Do not add outgoing bridge connection to session expiry list

Do not add outgoing bridge connection context to session expiry list

Fix sub_count is not decreased when client ubsubscribe

Fix define to properly parse bridge tcp user timeout configuration