Validate CSV output schemas

Also moved code dir to src.
There are reasons to do standard things in standard ways. While it is
possible to get the `code/` directory to work, and recognize it as a
package path, this requires wrangling the pyproject.toml file.
Additionally, any import from the `code.something` path automatically
shadows the python stdlib `code` module. While it may not be necessary,
it still is good to not shadow standard library modules.

code/unique.py

@@ -1,56 +0,0 @@
-import csv
-import json
-from pathlib import Path
-
-
-def unique_install_csv(input_dir: Path, output_dir: Path) -> None:
-    output_file = output_dir / "unique_installs.csv"
-    with open(output_file, "w") as fw:
-        writer = csv.writer(fw)
-        writer.writerow(["date", "unique"])
-
-        for j in input_dir.glob("*.json"):
-            with open(j) as fr:
-                date = j.stem
-                data: dict[str, object] = {}
-                try:
-                    data = json.load(fr)
-                except json.JSONDecodeError:
-                    print(f"WARN: Could not decode JSON data for file {j}")
-                    continue
-
-                if "UniqueInstalls" not in data or not isinstance(
-                    data["UniqueInstalls"], int
-                ):
-                    print(
-                        f"WARN: No correct json structure containing 'UniqueInstalls' field in file {j}"
-                    )
-                    continue
-
-                p_date = date
-                p_count = data["UniqueInstalls"]
-                writer.writerow([p_date, p_count])
-
-
-def ensure_dirs(input_dir: Path, output_dir: Path):
-    if not input_dir.is_dir():
-        raise ValueError
-    output_dir.mkdir(exist_ok=True, parents=True)
-
-
-def main(input: str, output: str) -> None:
-    input_dir = Path(input)
-    output_dir = Path(output)
-    ensure_dirs(input_dir, output_dir)
-    unique_install_csv(input_dir, output_dir)
-
-
-if __name__ == "__main__":
-    import sys
-
-    if not len(sys.argv) == 3:
-        print("Please provide exactly one input directory and one output directory.")
-        sys.exit(1)
-    inp = sys.argv[1]
-    out = sys.argv[2]
-    main(inp, out)