Create output dir instead of returning error for OCI artifacts

[FrenchBen]

When a user wants to pull an OCI artifact, and they provide a location as the output, they more than likely want the output to be created if it doesn't exist.
CMD modified:

• mod pull
• artifact pull

Instead of checking for its existence, it's better to attempt to create it.

• If it exists, nothing will happen
• if it's a file, you'll get an error
• if it doesn't exist, it will be created

The above allows for a smoother UX, instead of getting a generic error:

$ timoni mod pull oci://ghcr.io/stefanprodan/modules/redis --version 7.2.2 --output ./redis-oci 
12:48PM ERR invalid output path ./redis-oci

After the fix:

$ timoni mod pull oci://ghcr.io/stefanprodan/modules/redis --version 7.2.2 --output ./redis-oci
1:32PM INF extracted: ./redis-oci

Test with existing file:

$ touch redis-oci
$ timoni mod pull oci://ghcr.io/stefanprodan/modules/redis --version 7.2.2 --output ./redis-oci
1:32PM ERR error creating path ./redis-oci: mkdir ./redis-oci: not a directory

[stefanprodan]

LGTM

Thanks @FrenchBen