[RFE] Support OCI registries for charts

[clausa]

Is this RFE related to an Existing Problem? If so, please describe:

It seems that hauler does not support fetching Helm charts from OCI registries:

$ hauler version
 __    __       ___       __    __   __       _______ .______
|  |  |  |     /   \     |  |  |  | |  |     |   ____||   _  \
|  |__|  |    /  ^  \    |  |  |  | |  |     |  |__   |  |_)  |
|   __   |   /  /_\  \   |  |  |  | |  |     |   __|  |      /
|  |  |  |  /  _____  \  |  `--'  | |  `----.|  |____ |  |\  \----.
|__|  |__| /__/     \__\  \______/  |_______||_______|| _| `._____|
hauler: Airgap Swiss Army Knife

GitVersion:    1.0.2
GitCommit:     0674e0a
GitTreeState:  clean
BuildDate:     2024-04-15T16:37:17Z
GoVersion:     go1.21.9
Compiler:      gc
Platform:      darwin/arm64

$ hauler store add chart memcached --repo "oci://registry-1.docker.io/bitnamicharts/memcached"  -l debug 2> /dev/null
2024-04-18 11:25:56 DBG running cli command [hauler store add chart]
2024-04-18 11:25:56 DBG using store at /path/to/store
2024-04-18 11:25:56 INF adding 'chart' [memcached] to the store
2024-04-18 11:25:56 ERR looks like "oci://registry-1.docker.io/bitnamicharts/memcached" is not a valid chart repository or cannot be reached: object required

$ helm pull oci://registry-1.docker.io/bitnamicharts/memcached
Pulled: registry-1.docker.io/bitnamicharts/memcached:7.0.3
Digest: sha256:40a21252594826385a398101e1840a1f6c39379066812ef5a651a5517310e9b3

Describe Proposed Solution(s):

• Add OCI registry support for Helm charts

Describe Possible Alternatives:

• Use helm to fetch charts from OCI registries to a local folder first, but it kind of defeats the purpose of hauler.

Additional Context:

• N/A