Handle multiple repos and/or git modules

[jtpio]

Is your feature request related to a problem? Please describe.

JupyterLab git does not show any information about other repos listed in a .gitmodules file.

For example https://github.com/denoland/deno defines a .gitmodules file with the following content:

[submodule "tests/util/std"]
	path = tests/util/std
	url = https://github.com/denoland/deno_std
	shallow = true
[submodule "tests/wpt/suite"]
	path = tests/wpt/suite
	url = https://github.com/web-platform-tests/wpt.git
	shallow = true
[submodule "tests/node_compat/runner/suite"]
	path = tests/node_compat/runner/suite
	url = https://github.com/denoland/node_test.git
	shallow = true
[submodule "cli/bench/testdata/lsp_benchdata"]
	path = cli/bench/testdata/lsp_benchdata
	url = https://github.com/denoland/deno_lsp_benchdata.git
	shallow = true

If I do the following:

• git clone https://github.com/denoland/deno
• cd deno
• git submodule init
• git submodule update

The JupyterLab Git UI does not show anything about these modules from the top-level:

But if you navigate to one of the submodules then the UI detects the repo properly:

Describe the solution you'd like

Something like what VS Code does could be useful:

Describe alternatives you've considered

N/A

Additional context

• Python package version: 0.50.1

• Extension version: 0.50.1

• Git version: 2.43.0

• Operating System and its version: All