Allow module to specify another config key than their module name

Some module cannot just define their module db configuration key entry as their module
name because they define more services than just their db (e.g. indexer, scrubber, ...)

Related to T4284

swh/core/cli/db.py

@@ -256,20 +256,24 @@ def db_init(ctx, module, dbname, flavor, initial_version):
     default=False,
     show_default=True,
 )
+@click.option("--module-config-key", help="Module config key to lookup.", default=None)
 @click.pass_context
-def db_version(ctx, module, show_all):
+def db_version(ctx, module, show_all, module_config_key=None):
     """Print the database version for the Software Heritage.
 
     Example::
 
         swh db version -d swh-test
+        swh db version scheduler
+        swh db version scrubber --module-config-key=scrubber_db
 
     """
     from swh.core.db.db_utils import get_database_info, import_swhmodule
 
-    # use the db cnx from the config file; the expected config entry is the
-    # given module name
-    cfg = ctx.obj["config"].get(module, {})
+    # use the db cnx from the config file; the expected config entry is either the given
+    # module_config_key or defaulting to the module name (if module_config_key is not
+    # provided)
+    cfg = ctx.obj["config"].get(module_config_key or module, {})
     dbname = get_dburl_from_config(cfg)
 
     if not dbname:
@@ -328,14 +332,18 @@ def db_version(ctx, module, show_all):
     help="Do not ask questions (use default answer to all questions)",
     default=True,
 )
+@click.option(
+    "--module-config-key", help="Module configuration key to lookup.", default=None
+)
 @click.pass_context
-def db_upgrade(ctx, module, to_version, interactive):
+def db_upgrade(ctx, module, to_version, interactive, module_config_key):
     """Upgrade the database for given module (to a given version if specified).
 
     Examples::
 
         swh db upgrade storage
         swh db upgrade scheduler --to-version=10
+        swh db upgrade scrubber --to-version=10 --module-config-key=scrubber_db
 
     """
     from swh.core.db.db_utils import (
@@ -345,9 +353,10 @@ def db_upgrade(ctx, module, to_version, interactive):
         swh_set_db_module,
     )
 
-    # use the db cnx from the config file; the expected config entry is the
-    # given module name
-    cfg = ctx.obj["config"].get(module, {})
+    # use the db cnx from the config file; the expected config entry is either the given
+    # module_config_key or defaulting to the module name (if module_config_key is not
+    # provided)
+    cfg = ctx.obj["config"].get(module_config_key or module, {})
     dbname = get_dburl_from_config(cfg)
 
     if not dbname: