Add Path Manager to PCE Server Provider

Add Path Manager to PCE Server Provider

The goal of the new Path Manager is to improve the PCE Server.
Its main objectives are as follow:
- Ease the management of LSPs, in particular to update them without
  the need to manually compute a path
- Allow the possibility to provide an ERO to reported LSPs without
  a valid path
- Provide persistency of Initiated and Updated LSPs accross PCC and or
  PCE reboot

JIRA: BGPCEP-979
Change-Id: I0ea42958c5e46511c83d5b4c0c23bdc0a5321ed4
Co-authored-by: Guillaume Lambert <guillaume.lambert@orange.com>
Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>