pimd: Northbound implementation for rp commands.

pimd: Northbound implementation for rp commands.

ip_pim_rp
ip_pim_rp_prefix_list
no_ip_pim_rp
no_ip_pim_rp_prefix_list

module: frr-pim-rp

  augment /frr-routing:routing/frr-routing:control-plane-protocols/frr-routing:control-plane-protocol/frr-pim:pim/frr-pim:address-family:
    +--rw rp
       +--rw static-rp
          +--rw rp-list* [rp-address]
             +--rw rp-address                     ietf-inet-types:ip-address
             +--rw (group-list-or-prefix-list)?
                +--:(group-list)
                |  +--rw group-list*   ip-multicast-group-address-prefix
                +--:(prefix-list)
                   +--rw prefix-list?   plist-ref

Signed-off-by: Sarita Patra <saritap@vmware.com>