Restart of server fails because of disabled reuseaddr socket option

[keba-estr]

Description

Follow up of issue #6463

Background Information / Reproduction Steps

The provided fix with commit 00206cd does not work (at least on linux systems).
Although the function UA_EventLoopPOSIX_setReusable succeeds with UA_STATUSCODE_GOOD when closing the port,
the socket can not be opened sporadically at the next restart.
It seems that the socket option SO_REUSEADDR only has an effect if called before the function bind.

Checklist

Please provide the following information:

• open62541 Version (release number or git tag): 1.4
• Operating system: Linux

[jpfr]

In that case you best option is to set the reuseaddr configuration flag for your application.

open62541/include/open62541/server.h

Line 181 in 9229a2f

UA_Boolean tcpReuseAddr;

That way the socket is set reusable automatically.

[keba-estr]

We can set the option in the server.
@jpfr: However, the security point of view about this setting should be discussed in the next community call.

[jpfr]

Sure we can discuss.