WIP: Added ability to fetch flavor from url

[abdul-jabbar01]

Currently, Pligos only supports to load the flavor from local directory structure. But it doesn't support to fetch the pligos from any remote URL.

So, this PR will add this feature in pligos. This PR is somehow linked to this issue #25

[johnholiver]

@jostillmanns I've asked @abdul-jabbar01 to post this PR so we can have an initial idea on how this could be implemented.
Although this PR seems to work, I told him that a more interesting approach would be to use the capabilities from Helm and Chart Repositories to fetch flavors and, in that way, get hosting and versioning features for free. Basically buidling on top of what the helm codebase provides as libraries to load charts from Chart Repos.

It's my opinion that this PR should not be merged. Still, I feel like putting it up as a PR for all of us to see is a good opportunity to evaluate needed requirements and code around the feature. He is already looking into building another PR which considers the ideas aforementioned.

[jostillmanns]

I think we need to consider helm v3 when going forward with this. I know that some of the internal helm API has changed with the upcoming release. Maybe we should upgrade to helm v3 and then introduce this feature. Thoughts?

[abdul-jabbar01]

I think we need to consider helm v3 when going forward with this. I know that some of the internal helm API has changed with the upcoming release. Maybe we should upgrade to helm v3 and then introduce this feature. Thoughts?

Latest stable version of helm is still v2. So, I guess that we should wait until v3 will become stable release.