feat: Add logger

[alcb1310]

This PR will close issue #140

Adds structured logger to the application

Usage

Define your logs by priority: Debug, Info, Warn and Error by adding the following to the code

import log/slog

slog.Debug("Debug message")
slog.Info("Information message")
slog.Warn("Warning message")
slog.Error("Error message")

To set the debug level when running:

ENV=debug sesh

Just need to change the debug text for info or error. The default log level is warn.

[alcb1310]

Made some decisions to implement this, it will be good to have your input about those:

• Log file location: I decided to use the following ~/.config/sesh/<date>.log
• Log file name: I decided to use the date in the format YYYY-mm-dd as the log file name
• Default log level: If no log level is defined, I set being the warn level as the default one
• When using the default log level, I decided not to show the user the log information and only save the log to the specified file

[joshmedeski]

I'll review this and plan on merging it later this week, thanks!