[Core V3] Make the bot data path configurable (#879)

* Initial commit

* Fix sentry

* Make cog manager install path work relative to the bot's dir

* Fix downloader to save data relative to the defined data folder

* Fix sentry test

* Fix downloader tests

* Change logfile location

* Add another line to codeowners

* Basic tests

* Fix versioning

* Add in FutureWarning for config file changes

* Add reference to issue

core/data_manager.py

@@ -0,0 +1,61 @@
+from pathlib import Path
+
+from core.json_io import JsonIO
+
+jsonio = None
+basic_config = None
+
+basic_config_default = {
+    "DATA_PATH": None,
+    "COG_PATH_APPEND": "cogs",
+    "CORE_PATH_APPEND": "core"
+}
+
+
+def load_basic_configuration(path: Path):
+    global jsonio
+    global basic_config
+
+    jsonio = JsonIO(path)
+    basic_config = jsonio._load_json()
+
+
+def _base_data_path() -> Path:
+    if basic_config is None:
+        raise RuntimeError("You must load the basic config before you"
+                           " can get the base data path.")
+    path = basic_config['DATA_PATH']
+    return Path(path).resolve()
+
+
+def cog_data_path(cog_instance=None) -> Path:
+    """
+    Gets the base cog data path. If you want to get the folder with
+        which to store your own cog's data please pass in an instance
+        of your cog class.
+    :param cog_instance:
+    :return:
+    """
+    try:
+        base_data_path = Path(_base_data_path())
+    except RuntimeError as e:
+        raise RuntimeError("You must load the basic config before you"
+                           " can get the cog data path.") from e
+    cog_path = base_data_path / basic_config['COG_PATH_APPEND']
+    if cog_instance:
+        cog_path = cog_path / cog_instance.__class__.__name__
+    cog_path.mkdir(exist_ok=True, parents=True)
+
+    return cog_path.resolve()
+
+
+def core_data_path() -> Path:
+    try:
+        base_data_path = Path(_base_data_path())
+    except RuntimeError as e:
+        raise RuntimeError("You must load the basic config before you"
+                           " can get the core data path.") from e
+    core_path = base_data_path / basic_config['CORE_PATH_APPEND']
+    core_path.mkdir(exist_ok=True, parents=True)
+
+    return core_path.resolve()