Refactor: extract summarize_build into its own subroutine
Replace mkdir calls with create_directory
Refactor: Extract method summarize_individual
Refactor: extract method summarize_sample
Rename summarize_build to summarize_clinseq_build

The ClinSeq build itself summarizes many of its member builds, so
disambiguate this method.
Refactor: Call direct processing_profile accessor instead of get with id
Remove trailing whitespace s/\s+$//g
Refactor: filter undef out of @builds at beginning

Eliminates the need for "next unless $build" in each section.
Refactor: get type_name directly from the build.

Eliminates unneeded accesses to the model and processing-profile.
Refactor: Extract duplicated logic for determining WGS/exome
Refactor: remove extra indirection to get subject

We're calling can directly on a $subject, so call the method
on the same $subject.