get rid of 'db'subst' and 'ioc.substitution' + make default generate output in /tmp

[gilesknap]

The substitution file should always be called ioc.subst so ibek generate looks for :

• ioc.yaml
• st.cmd
• ioc.subst
• start.sh

and generates from yaml:

• st.cmd
• ioc.subst
• ioc.db

I believe this has been fixed throughout ibek and the scripts that use it but there is at least one place this is still wrong:

def generate(
    instance: Path = typer.Argument(
        ..., help="The filepath to the ioc instance entity file"
    ),
    definitions: List[Path] = typer.Argument(
        ..., help="The filepath to a support module definition file"
    ),
    out: Path = typer.Option(
        default="config/st.cmd",
        help="Path to output startup script",
    ),
    db_out: Path = typer.Option(
        default="config/db.subst",
        help="Path to output database expansion shell script",
    ),
):

defaults SHOULD be

• out = /tmp/st.cmd
• db_put = /tmp/ioc.subst

[gilesknap]

done in f7d82deb08596c5a7761eeba70f11ee123a1f5da