Split out the local backend (#2052)

This splits the backend into two parts: the local backend for desktop cellxgene and the AWS backend for hosted cellxgene. The local backend is in local_server while the hosted remains in server. The general idea is to copy everything from server to local_server, pull unneeded stuff out of local_server, and keep server as-is for this PR. Not touching server means all the infra and deployment code will continue working just as it did before so we can make those changes incrementally.

local_server/cli/cli.py

@@ -0,0 +1,33 @@
+import click
+
+from .launch import launch
+from .prepare import prepare
+from .upgrade import log_upgrade_check
+from .schema import schema_cli
+from .. import __version__
+
+
+@click.group(
+    name="cellxgene",
+    subcommand_metavar="COMMAND <args>",
+    options_metavar="<options>",
+    context_settings=dict(max_content_width=85, help_option_names=["-h", "--help"]),
+)
+@click.help_option("--help", "-h", help="Show this message and exit.")
+@click.version_option(
+    version=__version__,
+    prog_name="cellxgene",
+    message="[%(prog)s] Version %(version)s",
+    help="Show the software version and exit.",
+)
+@click.option(
+    "--upgrade-check/--no-upgrade-check", default=True, show_default=True, help="Check for release upgrades on start.",
+)
+def cli(upgrade_check):
+    if upgrade_check:
+        log_upgrade_check()
+
+
+cli.add_command(launch)
+cli.add_command(prepare)
+cli.add_command(schema_cli)