[DPM] Refactor db/cache codes to support GoalStateV2 design

[DavidLiu506]

1. Implement data plane manager cache design for GoalStateV2.
2. Move neighbor functionality from PM to DPM.

[lgtm-com[bot]]

This pull request introduces 1 alert and fixes 3 when merging 43c0c7c42d519e202b1d635c8f38ea8c039a792e into 97fc7b8482320f121889dd4211f71b29a77d6275 - view on LGTM.com

new alerts:

• 1 for Self assignment

fixed alerts:

• 3 for Useless null check

[lgtm-com[bot]]

This pull request introduces 1 alert and fixes 3 when merging f5b7f75f85a591bde9b5cb7f41cc70627ed1cd3b into d3354defaf316b37bd602a739003d7d1e78428a2 - view on LGTM.com

new alerts:

• 1 for Self assignment

fixed alerts:

• 3 for Useless null check

[xieus]

@DavidLiu506 All looks good. There is a merge conflict for the file services/network_config_manager/src/main/java/com/futurewei/alcor/netwconfigmanager/client/gRPC/GoalStateClientImpl.java likely due to merging other PRs to master. Could you resolve the conflict quickly so that I could push this PR to master.

[lgtm-com[bot]]

This pull request introduces 1 alert and fixes 3 when merging d9965591a7393275b81684ff2baee948f95b3c7b into 42a6edcd6e6341a3aedc6f87c87c4c66958c0072 - view on LGTM.com

new alerts:

• 1 for Self assignment

fixed alerts:

• 3 for Useless null check