Fix pulp-cli-deb missing pulpexport capability

[tjmullicani]

Closes #40

[lubosmj]

Can this PR be accepted by someone from @pulp/debian?

[quba42]

I have not been so involved with the import/export feature, and I know we are still struggling to get this feature working within Katello (the only place were the plugin maintainers actively use it): https://community.theforeman.org/t/support-importing-content-views-with-deb-content-with-hammer-content-import/31178

As a result I am unsure how well the feature works on the Pulp side, and if it is wise to make it easier to use via pulp CLI.

@hstct @mdellweg @Manisha15 Do you have any opinions on how best to continue? (Any of you have time to test this?)

[Manisha15]

I have not been so involved with the import/export feature, and I know we are still struggling to get this feature working within Katello (the only place were the plugin maintainers actively use it): https://community.theforeman.org/t/support-importing-content-views-with-deb-content-with-hammer-content-import/31178

As a result I am unsure how well the feature works on the Pulp side, and if it is wise to make it easier to use via pulp CLI.

@hstct @mdellweg @Manisha15 Do you have any opinions on how best to continue? (Any of you have time to test this?)

I have tested it on pulp side and it worked fine and the PR is also merged on pulp side. I can test it using via pulp CLI as it can also verify if it working on pulp side properly or not and if the issue is only on Katello side or on pulp side as well.

[quba42]

@Manisha15 If you can review this PR (test the feature using pulp-cli with these changes), then I am happy to merge this.

It also looks like this does not need a test other than the ones already in place for the pulpcore feature. (None of the other content plugins have their own separate tests for import/export)