Add TPV rule for SPAdes --frugal mode to reduce memory allocation

SPAdes (and rnaSPAdes) now expose a `--frugal` flag (added in tools-iuc#8104) that enables a memory-frugal assembly mode, trading some potential assembly quality for reduced RAM usage.

Could we add a TPV rule for SPAdes tools that detects when `--frugal` is set and allocates a reduced memory ceiling accordingly. Without such a rule, the --frugal option has limited practical effect from a scheduling perspective - the job will still be assigned the default (higher) memory, making the flag less useful.