What is the collective word for any semi-literate person that you can hire

Tradesman is about as close as it gets for a single-word umbrella term.

AHD

1. A man who practices a manual trade.

trade

6. An occupation, especially one requiring skilled labor; craft: the building trades.

Wikipedia

A tradesman, skilled tradesman, or tradie refers to a worker who specializes in a particular occupation that requires work experience, on-the-job training, and often formal vocational education, but not a bachelor's degree.

Skilled worker also comes close, but doesn't have the blue-collar connotations that tradesman does.

Wikipedia

A skilled worker is any worker who has special skill, training, knowledge, and (usually acquired) ability in their work. A skilled worker may have attended a college, university or technical school. Or, a skilled worker may have learned their skills on the job. Examples of skilled labor include engineers, scientists, software development, paramedics, police officers, soldiers, physicians, crane operators, cdl truck drivers, machinist, drafters, plumbers, craftsmen, cooks and accountants. These workers can be either blue-collar or white-collar workers, with varied levels of training or education, even though they sometimes are called "purple collars".