Feature 9952: Distributed Proxy Charms

This feature allows to specify the destination clouds for Proxy Charms
associated with a specific VIM Account

- Remove N2VCJujuConnectorLCM usage.
- Parse VIM config parameters to get vca_k8s_cloud,
vca_k8s_cloud_credential, vca_cloud, and vca_cloud_credential
parameters.
- Pass the above parsed parameters to N2VC

Change-Id: I660d9b7245ae30d8fdc0dc3df470ee003abbba75
Signed-off-by: David Garcia <david.garcia@canonical.com>