LISP CP cleanup and refactoring

LISP CP cleanup and refactoring

- avoid code duplication by using only one function for
  insertion/updating of remote mappings into map-cache. Static remote
  mappings are now inserted using this function as well and therefore
  the code does not try to build forwarding entries out of them now.
- bring up lisp dp interfaces when a vni is bound to a vrf.
- ensure eids are cleaned-up before parsing control plane messages
- ensure map-requests are always sent to default fib
- new API to insert lisp adjacencies as opposed to remote mappings which
  should be replaced post merged in CSIT
- reorganize and group functions according to their purpose and use. No
  need to pre-declare internal functions now.
- this does not touch locator-set logic

Change-Id: Ibcfc0f2d9c1bc1c9eab6e83c1af1b4cf9302ac10
Signed-off-by: Florin Coras <fcoras@cisco.com>