[feature] removes Pipfile and adds requirements.txt file

A "requirements.txt" CI test is also added to make sure this file is
up to date with the Nix environment used in CI.
21 jobs for requirements2 in 4 minutes and 2 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Style
passed #37784
integration
flake8

00:00:05

 
  Build
passed #37788
integration
buildAMG

00:00:04

passed #37791
integration
buildLAMMPS

00:00:04

passed #37789
integration
buildOpenMC

00:00:04

passed #37790
integration
buildSTREAM

00:00:04

passed #37787
integration
containers

00:00:04

passed #37786
integration
libnrm

00:00:04

passed #37785
integration
nrm

00:00:07

 
  Test
passed #37792
integration
requirements.txt

00:00:07

passed #37795
integration
testHello

00:00:15

passed #37796
integration
testListen

00:00:18

passed #37797
integration performance
testPerfwrapper

00:00:55

passed #37798
knl
testPower

00:00:54

passed #37793
integration
testPwd

00:00:16

passed #37794
integration
testRun

00:00:16

passed #37799
singularity
testSingularity

00:00:15

 
  Applications
passed #37800
notknl integration
testAMG

00:00:22

passed #37803
notknl integration
testLAMMPS

00:00:17

passed #37802
notknl integration
testOpenMC

00:00:55

passed #37801
notknl integration
testSTREAM

00:00:19

 
  Quality
passed #37804
integration
repoquality

00:00:07