Multiple line items on service orders

Service orders currently only allow one line item, but most real-world service jobs combine multiple things — cleaning + lettering + leveling, plus per-letter pricing and affidavit fees. Right now I have to put the total on one line and itemize in the description, which is messy.

Half the lettering jobs we do also end up cleaning the stone, so this comes up constantly. A typical breakdown looks like: etching $1,500 + first 21 letters $685 + 32 letters × $9 = $288 + affidavit $150 = $2,773.

Let service orders accept multiple line items the same way monument orders do.