change the build system type detection to not rely on the ref data signature

The logic to detect the build system type was based on the reference
data signature on the job table to match at least one signature on the
reference_data_signatures table. This is not always true as reported in
https://bugzilla.mozilla.org/show_bug.cgi?id=1033107.
The new logic is inspecting the reference_data_signature table to
retrieve a dictionary of repo => build system type that is cached.
Merge pull request #177 from mozilla/1033107-quickfix

change the build system type detection to not rely on the refdata signature
add high priority queue for tbpl-related tasks
add supervisord configuration for the hp worker
Merge pull request #178 from mozilla/hp-task-queue

add high priority queue for tbpl-related tasks
convert bug suggestions to list, rather than object
fix bug suggestions
fixing test mocking
Merge branch 'bug-suggestions-order' of github.com:mozilla/treeherder-service into bug-suggestions-order
Fixed bug suggestions to match all error lines from the log