cephadm-dashboard-e2e: replace docker with podman

[nizamial09]

• cleanup the docker installation.

[nizamial09]

i haven't tested this in the jenkins yet by updating the job configuration yet. Only done it in my local VM (which worked fine). Will wait for an approval before testing it out in the jenkins machines.

[nizamial09]

replacing docker with podman.

[dmick]

This is good as far as it goes, but I see two problems:

1. there are build hosts that have installed docker in the standard way from the standard repos, and rely on it, so "is docker present, if so remove it" is going to break those hosts

2. the broken hosts will stay broken until they happen to be selected for a dashboard run

so this isn't sufficient, and I don't have time to make it better this week

[nizamial09]

1. there are build hosts that have installed docker in the standard way from the standard repos, and rely on it, so "is docker present, if so remove it" is going to break those hosts

@dmick i've modified the condition to check whether docker is installed through the docker official repo (docker-ce) and then only remove it. Maybe its more safer than before. Again I tried this out in my local VM which succesfully worked.