Development: use ssh agent forwarding

[yelizariev]

This is a lifeboat for Tecnativa/doodba-scaffolding#72

Before I make a pull request for copier template, @yajo could you tell me your general view of the issue and solution

[yajo]

Well, as you can see now we have a better infrastructure to handle that.

IMHO that logic should go into

doodba-copier-template/tasks_downstream.py

Lines 82 to 97 in 687326a

	@task(develop)
	def git_aggregate(c):
	"""Download odoo & addons git code.
	Executes git-aggregator from within the doodba container.
	"""
	c.run(
	"docker-compose --file setup-devel.yaml run --rm odoo",
	env={"GID": os.getgid(), "UID": os.getuid(), "UMASK": 27},
	)
	_write_code_workspace_file()
	for pre_commit_folder in iglob(
	str(SRC_PATH / "*" / ".git" / ".." / ".pre-commit-config.yaml" / ".")
	):
	with c.cd(pre_commit_folder):
	c.run("pre-commit install")

so that, if possible, we reuse host's SSH auth socket automatically.

It could be disabled by a CLI flag so that we are able to reproduce what would happen without that easily.

[yelizariev]

I just noticed that this was also discussed in Tecnativa/doodba#292