Add multiselect function to system module

[sujyotraut]

https://github.com/SilentVoid13/Templater/assets/70472979/c9fba4e8-8d39-40ef-9fb1-5d7e79342dfe

This PR solves the issue #461 & #1130 by adding multiselect internal function to the system module.

https://github.com/SilentVoid13/Templater/assets/70472979/c303a393-37c7-469a-a744-1165bb5b98c8

It adds new lines to the start of the file. Is it only happening in my system or same happens in others as well. Please tell me if it is same on your system as well, and provide feedback on how to solve it if possible.

[sujyotraut]

It add new lines at the start of the file after the result is returned. I can't quite figure out why it's happening or is it just happening in my system, please let me know if it's just happening in my system or same happens on others as well.

https://github.com/SilentVoid13/Templater/assets/70472979/c303a393-37c7-469a-a744-1165bb5b98c8