Update to node 8

[carbonin]

This PR adds a repo(https://rpm.nodesource.com/pub_8.x/el/7/x86_64/) during build from which we can install an rpm (nodesource-release) which brings a repo file which allows us to install nodejs version 8.

This also removes npm because the new node package also provides /usr/bin/npm

[root@localhost vmdb]# rpm -qa | grep node
nodesource-release-el7-1.noarch
nodejs-8.11.3-1nodesource.x86_64
[root@localhost vmdb]# rpm -qa | grep npm
[root@localhost vmdb]# which npm
/usr/bin/npm
[root@localhost vmdb]# yum provides /usr/bin/npm
2:nodejs-8.11.3-1nodesource.x86_64 : JavaScript runtime
Repo        : nodesource
Matched from:
Filename    : /usr/bin/npm

1:npm-3.10.10-1.6.14.3.1.el7.x86_64 : Node.js Package Manager
Repo        : epel
Matched from:
Filename    : /usr/bin/npm

cc @himdel

[miq-bot]

Checked commits carbonin/manageiq-appliance-build@8cb67f8~...a62aa07 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
0 files checked, 0 offenses detected
Everything looks fine. 🍪