tmf: Make process and thread names optional in call stack state provider

tmf: Make process and thread names optional in call stack state provider

- Update call stack state provider to allow the optional specification
of the process name for an event.

- Make the specification of the thread name for an event optional.

- Use the process id (or UKNOWN) as attribute name if the process name
is unspecified.

- Use the thread id as attribute name if the thread name is unspecified.

- Store the process id as int state value of the process attribute in
the default state provider implementation.

- Update call stack view to use the process attribute's int state value
for the process id if available, otherwise try to use the attribute name
parsed as an int.

- Use the thread attribute's long state value for the thread id if
available, otherwise try to use the attribute name parsed as a long.

Change-Id: I91fc5d3eaebaaeed6f44009a1e2185a0bfe6a878
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/71824
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>