Start a new sidecar container in the Sandbox. The Image must
already be built by calling Image.build() before it is
passed to create.
Optionalparams: SidecarCreateParamsReturn a sidecar container by name.
Optionalparams: SidecarGetParamsReturn all sidecar containers (not including the main container).
Optionalparams: SidecarListParams
Creates and manages sidecar containers inside a Sandbox.
EXPERIMENTAL: the API is subject to change.