Add support for log file at various logging levels

[dasupradyumna]

Context

Given that Rust is not an interpreted language like Lua, debugging it is not as straightforward as adding print statements since that would require recompiling the binary. A clean solution would be support logging at various levels of granularity as and when needed by the user. This would allow the user to communicate their problems efficiently with the maintainer, with the state or variables being logged depending on logging levels.

Proposal

• Create and setup a log file for the plugin in the data directory.
• Provide a user setting to control the logging level
• Add logging code in the project, based on the set log level