[processor/transform] Add merge_maps and ParseJSON functions

[TylerHelmuth]

Description:
Adds the merge_maps and ParseJSON functions.

Link to tracking Issue:
Related to #9410
Related to #14938

Testing:
Added unit tests

Documentation:

[runforesight]

Foresight Summary

    
Major Impacts

build-and-test duration(41 minutes 30 seconds) has decreased 13 minutes 10 seconds compared to main branch avg(54 minutes 40 seconds).

View More Details

⭕  build-and-test-windows workflow has finished in 4 seconds (32 minutes 28 seconds less than main branch avg.) and finished at 1st Dec, 2022.

---

Job	Failed Steps	Tests
windows-unittest-matrix	-     🔗	N/A	See Details
windows-unittest	-     🔗	N/A	See Details

---

✅  changelog workflow has finished in 2 minutes 8 seconds (3 minutes 8 seconds less than main branch avg.) and finished at 1st Dec, 2022.

---

Job	Failed Steps	Tests
changelog	-     🔗	N/A	See Details

---

🔎 See details on Foresight

^{*You can configure Foresight comments in your organization settings page.}