feat: create libretime_shared package (#1349)

* feat: create libretime_shared package

- We don't use pydantic.BaseSettings because of some
  incompatble loading behavior.

* fix: whitelist pydantic in pylintrc

* docs: update to new BaseConfig behavior

* docs: change confusing config filepath

shared/tests/logging_test.py

@@ -0,0 +1,47 @@
+from pathlib import Path
+
+import pytest
+from loguru import logger
+
+from libretime_shared.logging import (
+    create_task_logger,
+    level_from_verbosity,
+    setup_logger,
+)
+
+
+@pytest.mark.parametrize(
+    "verbosity,level_name,level_no",
+    [
+        (-100, "error", 40),
+        (-1, "error", 40),
+        (0, "warning", 30),
+        (1, "info", 20),
+        (2, "debug", 10),
+        (3, "trace", 5),
+        (100, "trace", 5),
+    ],
+)
+def test_level_from_verbosity(verbosity, level_name, level_no):
+    level = level_from_verbosity(verbosity)
+    assert level.name == level_name
+    assert level.no == level_no
+
+
+def test_setup_logger(tmp_path: Path):
+    log_filepath = tmp_path / "test.log"
+    extra_log_filepath = tmp_path / "extra.log"
+
+    setup_logger(1, log_filepath)
+
+    extra_logger = create_task_logger(2, extra_log_filepath, True)
+
+    logger.info("test info")
+    extra_logger.info("extra info")
+    logger.debug("test debug")
+
+    extra_logger.complete()
+    logger.complete()
+
+    assert len(log_filepath.read_text().splitlines()) == 1
+    assert len(extra_log_filepath.read_text().splitlines()) == 1