Refactor angle utilities into separate module

I am preparing to use these from another module. I have to
refactor these methods to avoid an import loop.
9 jobs for angle-refactored in 36 minutes and 39 seconds (queued for 1 second)
Status Job ID Name Coverage
  Nightly
passed #25448
macos
nightly:macos

00:34:29

passed #25445
nightly:mpi:jessie

00:36:06

passed #25446
nightly:openmp:jessie

00:35:59

passed #25447
nightly:python3:stretch

00:36:36

failed #25444
allowed to fail
nightly:top-level:buster

00:21:10

passed #25440
nightly:top-level:el7

00:33:53

passed #25441
nightly:top-level:stretch

00:36:30

passed #25442
nightly:top-level:trusty

00:28:21

passed #25443
nightly:top-level:xenial

00:30:23

 
Name Stage Failure
failed
nightly:top-level:buster Nightly There is an unknown failure, please try again
Makefile:403: recipe for target 'check-recursive' failed
make[2]: *** [check-recursive] Error 1
make[2]: Leaving directory '/builds/leo-singer/lalsuite/lalsuite-6.48.1/_build/sub'
make[1]: *** [check] Error 2
Makefile:677: recipe for target 'check' failed
make[1]: Leaving directory '/builds/leo-singer/lalsuite/lalsuite-6.48.1/_build/sub'
make: *** [distcheck] Error 1
Makefile:594: recipe for target 'distcheck' failed
ERROR: Job failed: exit code 1