[PR 1/X] basic plumbing for serde support for expressions

[evindj]

Summary

This is the first PR aimed a addressing #331
Because doing it in one go will be more error prone and will make review harder, I am splitting the change across several PR.
This first one covers:

• Template definition to help generate ToJson and FromJson implementations.
• basic support for only boolean expressions.
• Unit tests for the case that we was added.

Test

• Added some unit tests that cover the change and ensured the pass
   ~/Documents/my_iceberg/iceberg-cpp   bool_expressio_serde  ./build/src/iceberg/test/expression_test --gtest_filter="ExpressionJson*"  ✔  1297  13:53:47
  Running main() from gmock_main.cc
  Note: Google Test filter = ExpressionJson*
  [==========] Running 2 tests from 1 test suite.
  [----------] Global test environment set-up.
  [----------] 2 tests from ExpressionJsonTest
  [ RUN ] ExpressionJsonTest.TrueExpression
  [ OK ] ExpressionJsonTest.TrueExpression (0 ms)
  [ RUN ] ExpressionJsonTest.FalseExpression
  [ OK ] ExpressionJsonTest.FalseExpression (0 ms)
  [----------] 2 tests from ExpressionJsonTest (0 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test suite ran. (0 ms total)
[ PASSED ] 2 tests.
idjiofack@Innocents-MacBook-Pro-2  ~/Documents/my_iceberg/iceberg-cpp   bool_expressio_serde 