First draft of codespeedization of test/perf.

To use, run `make codespeed` in `test/perf`
Update default unit titles
Expect env variables instead of Base.BUILD_INFO for now
Annotate new BLAS tests for codespeed
typos!
Add blas tests into the Makefile so `make codespeed` gets them as well
Be a little more assertive with how we use JSON and Curl.  Also only check for environment variables when codespeed is true
usingmodule()!  Who would have guessed!
BLAS is phony too
Finally understand what unit_title is good for, and immediately rename it.  Sort benchmarks by an optional `group` string, which defaults to the name of the benchmark folder it's in (e.g. blas, micro, etc...)
I like uppercase BLAS
Aaaand, forgot a dollar sign
Reinclude BLAS.  Thanks @loladiro.
Ah, yes, some tests use timeit1 as well...
Revert rename, as suggested by @vtjnash due to case-insensitive filesystems
Send webhook notifications to julia.mit.edu now, instead of the codespeed server proper
Tricksy little Consies!