Allow specifying Time Zone in Parser

The Parser Filter allows a user to set the Time System Zone (https://docs.fluentbit.io/manual/pipeline/parsers/configuring-parser). This works great when the log has the following properties

(1) Does not contain a Timezone specified in GNU format
(2) Is the same Timezone as the system that is sending the message

In the case where a known log is in a certain timezone, which is different than the logs origin, the only way to have accurate timings is to use the Time Offset. This presents a lot of manual overhead with synchronizing Daylight Savings vs. specifying the Time Zone manually

Ideally a user can not just set a Time_System_Zone as binary, BUT also specify the GNU format Timezone (https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html)