feat: stdout logging capabilities

- Added feature "stdout_logging" (see README)
- Added config.loglevel option (see config.toml)
- Logging some common things
- Hopefully fix on_new_day_started

Cargo.toml

@@ -5,6 +5,8 @@ edition = "2021"
 
 [dependencies]
 chrono = "0.4.42"
+colog = { version = "1.4.0", optional = true }
+log = { version = "0.4.29", features = ["serde"] }
 serde = "1.0.219"
 slint = "1.15.1"
 toml = "1.1.2"
@@ -16,5 +18,7 @@ slint-build = "1.15.1"
 opt-level = 3
 
 [features]
+default = ["stdout_logger"]
 light = []
 dark = []
+stdout_logger = ["colog"]