Allow extract_path to be modified

[treydock]

Pull Request (PR) description

Remove hardcoded extract_path. I ran into a few exporters where the binary is all that is extracted from tar.gz so necessary to create the extract path directory in profile then set this new parameter to that value.

Good example: https://github.com/ribbybibby/ssl_exporter/releases

[ghoneycutt]

Thanks for the contribution! Could you please add a test of some kind for the new parameter.

[treydock]

Added unit test for changing from the default value, the default value was already being tested.

[ghoneycutt]

Tests are failing though I think it is unrelated. Seeing this in the travis output.

Error: /Stage[main]/Prometheus::Haproxy_exporter/Prometheus::Daemon[haproxy_exporter]/Archive[/tmp/haproxy_exporter-0.7.1.tar.gz]/ensure: change from 'absent' to 'present' failed: Execution of '/opt/puppetlabs/puppet/bin/curl https://github.com/prometheus/haproxy_exporter/releases/download/v0.7.1/haproxy_exporter-0.7.1.linux-amd64.tar.gz -o /tmp/haproxy_exporter-0.7.1.tar.gz_20200518-2581-dj4ovu -fsSLg --max-redirs 5' returned 22: curl: (22) The requested URL returned error: 429 too many requests

Perhaps travis needs a github token to get past that?