Add new file log4j-graylog2-web-interface.xml

https://github.com/corey-hammerton/graylog2-rpms/issues/2

As what was completed for the graylog2-server package, externalizing
the log4j configuration for the graylog2-web-interface must also
be completed. The contents of this file were taken from the
graylog2-web-interface documentation and modified to that the
behaviour mimics the graylog2-server configuration, even though the
classes here are different.

Initial testing for this configuration file needs to be completed
before I will include this file in the SPEC file.
Adding the log4j configuration for the web-interface to the main tree

Adding a sleep command in the result function of
SOURCES/init.d-graylog2-web-interface, because running a simple
stop and restart causing an exception because a port is already
in use because the services hasn't shut down yet before a start
was attempted.

Exiting with code 1 if the JAVA_CMD variable is not executable in
SOURCES/init.d-graylog2-web-interface

Removing the file redirection from the start command in
SOURCES/init.d-graylog2-web-interface. Since the new log4j config
no longer outputs to System.out/stdout a file redirection is not
needed.

Removing the commented classpath variable from
SOURCES/sysconfig-graylog2-web-interface, it contains the list of
individual jar files in the lib directory. Making this file another
thing to update on version updates, besides, any problems that may
occur for users will be based on their setup.

Including and installing the log4j-graylog2-web-interface.xml file
from SPECS/graylog2-web-interface.spec under /etc/graylog2/.
Officially adding it to the rpm building process.
Removing original logrotate source and spec file references.

https://github.com/corey-hammerton/graylog2-rpms/issues/2

Removing source file SOURCES/logrotate.d-graylog2 since logging
is now managed by log4j which is using it's own rotation
mechanism. There is no longer any technical reason to have a
server level logrotation process happening.

Removing all references to SOURCES/logrotate.d-graylog2 in
SPECS/graylog2-server.spec and SPECS/graylog2-web-interface.spec.
Did this by replacing source 3 with source 4 then removed all
lines that contained logrotate.

Removing the unsed SOURCES/log4j.xml file. This file was added when
this issue was initially create before any documentation for server
and web-interface logging was available.