Create OpenLMIS API end-points

[vincent-karuri]

• [x] Implement TradeItem /get end-point to get a list of all TradeItems
• [x] Implement CommodityType /get end-point to get a list of all CommodityTypes
• [x] Implement Program /get end-point to get a list of all Programs
• [x] Implement Orderable /get end-point to get a list of all Orderables
• [x] Implement ProgramOrderables /get end-point to get a list of all ProgramOrderables
• [x] Implement Lot /get end-point to get a list of all Lots
• [x] Implement Reason /get end-point to get a list of all Reasons
• [x] Implement Location /get end-point to get a list of all Locations specific to a user
• [x] Implement TradeItemClassification /get end-point to get a list of all TradeItemClassifications
• [x] Implement TradeItem /add end-point to post new TradeItems
• [x] Implement CommodityType /add end-point to post new CommodityTypes
• [x] Implement Program /add end-point to post new Programs
• [x] Implement Orderable /add end-point to post new Orderables
• [x] Implement Lot /add end-point to post new Lots
• [x] Implement Reason /add end-point to post new Reasons
• [x] Implement ProgramOrderable /add end-point to post new ProgramOrderables
• [x] Implement TradeItemClassification /add end-point to post new TradeItemClassifications
• [x] Implement TradeItem /sync end-point to sync TradeItems by server version
• [x] Implement CommodityType /sync end-point to sync CommodityTypes by server version
• [x] Implement Program /sync end-point sync Programs by server version
• [x] Implement Orderable /sync end-point sync Orderables by server version
• [x] Implement ProgramOrderable /sync end-point sync ProgramOrderables by server version
• [x] Implement Lot /sync end-point to get a list of all Lot by server version
• [x] Implement Reason /sync end-point to get a list of all Reasons by server version
• [x] Implement TradeItemClassification /sync end-point to sync TradeItemClassifications by server version
• [x] Implement TradeItem /update end-point to update existing TradeItems
• [x] Implement CommodityType /update end-point to update existing CommodityTypes
• [x] Implement Program /update end-point to update existing Programs
• [x] Implement Orderable /update end-point to update existing Orderables
• [x] Implement Lot /update end-point to update existing Lots
• [x] Implement Reason /update end-point to update existing Reasons
• [x] Implement ProgramOrderable /update end-point to update existing ProgramOrderables
• [x] Implement TradeItemClassification /update end-point to update existing TradeItemClassifications
• [x] Add tests
• [x] Add required files for war file build

[githengi]

• [x] On the master_table the server version in JSON is 0, while the one in the server_version column is different.
• [x] GET and sync endpoints returns server version 0 for the trade-items
• [ ] For server_version use System.currentTimeMillis() instead of System.nanoTime(). System.nanoTime() is based on random reference and invocation in different thread will result in different values(Its not thread safe)