By Francesco Guarascio and Phuong Nguyen HANOI (Reuters) -A German business delegation, including top firms for tunnel machines, wind farms and industrial supplies, joined President Frank-Walter Steinmeier in a visit to Vietnam starting on Tuesday, as Berlin strives to reduce its reliance on China. German companies have invested over $3 billion in the Southeast Asian manufacturing hub, led by automotive giant Bosch, according to the German chamber of commerce in Vietnam. During the visit, Steinmeier and German labour minister Hubertus Heil signed a memorandum of understanding with their Vietna…