[Nexthop][M4062NHP] Add Platform Manager support

**Pre-submission checklist**
- [x] I've ran the linters locally and fixed lint errors related to the
files I modified in this PR. You can install the linters by running `pip
install -r requirements-dev.txt && pre-commit install`
- [x] `pre-commit run`

**Summary
Add platform_manager.json for the M4062nhp platform, modeling the SCM
and SMB PmUnits (PCI/I2C/FPGA topology, chassis EEPROM, port LEDs, fans,
PSUs) per the Platform Manager spec. Also add a ConfigLibTest case that
deserializes and validates the committed config.

**Test Plan
Validated the JSON parses and conforms to
platform_manager_config.thrift.
Built the BSP kmods RPM from nexthop-ai/nexthop.fboss.bsp.kmods and
confirmed it provides every module in requiredKmodsToLoad.
Added a ConfigLibTest case that deserializes and runs ConfigValidator
on the committed config.

Author: anna-nexthop

cmake/PlatformPlatformManagerTest.cmake

@@ -9,6 +9,7 @@ add_executable(platform_manager_config_validator_test
 
 target_link_libraries(platform_manager_config_validator_test
   platform_manager_config_validator
+  platform_config_lib
   Folly::folly
   ${GTEST}
   ${LIBGMOCK_LIBRARIES}

fboss/platform/config_lib/ConfigLibTest.cpp

@@ -18,6 +18,7 @@ const std::string kJanga800bic = "janga800bic";
 const std::string kTahan800bc = "tahan800bc";
 const std::string kBlackwolf800banw = "blackwolf800banw";
 const std::string kSample = "sample";
+const std::string kM4062nhp = "m4062nhp";
 const std::string kNonExistentPlatform = "nonExistentPlatform";
 } // namespace
 
@@ -52,6 +53,7 @@ TEST(ConfigLibTest, Basic) {
   EXPECT_NO_THROW(ConfigLib().getPlatformManagerConfig(kMeru800bia));
   EXPECT_NO_THROW(ConfigLib().getPlatformManagerConfig(kMeru800bfa));
   EXPECT_NO_THROW(ConfigLib().getPlatformManagerConfig(kMontblanc));
+  EXPECT_NO_THROW(ConfigLib().getPlatformManagerConfig(kM4062nhp));
   EXPECT_NO_THROW(ConfigLib().getPlatformManagerConfig(kMorgan800cc));
   EXPECT_NO_THROW(ConfigLib().getPlatformManagerConfig(kJanga800bic));
   EXPECT_NO_THROW(ConfigLib().getPlatformManagerConfig(kTahan800bc));