assembly memory estimation

[mflynn-lanl]

Is your feature request related to a problem? Please describe.
Get estimate for the amount of memory required for assembly. Use this estimate to set memory field in runtime and fail the workflow if memory exceeds amount available on backend

Describe the solution you'd like
Create a task that gets the number of unique kmers for a fastq file

Additional context
Brian Foster has a shell script that we will use as a starting point