[META]Add Missing PPL commands - campaign

[YANG-DB]

Is your feature request related to a problem?
Currently the existing Spark based PPL driver only covers a subset of the the OpenSearch based PPL Driver
We need to create a parity match to allow a seamless and transparent transition between the two and allow users to operate similar query regardless of their execution driver.

What solution would you like?
The following list of commands are missing from Spark Based PPL Driver:

---

PPL Missing Spark commands campaign

Correlation Commands

• - Lookup - PPL Lookup #407

Conditional Commands

• - IF ELSE - [FEATURE]Support complex predicates for IF function in PPL #398

String Commands

• - concat - [FEATURE]Add PPL Concat command  #419
• - LENGTH - [FEATURE]Add LENGTH PPL command #420
• - dedup - [FEATURE]Add dedup PPL Command #421
• - lower - [FEATURE]Add lower ppl command #422
• - ltrim - [FEATURE]Add ltrim PPL command #423
• - rtrim - [FEATURE]Add rtrim PPL command #425)
• - trim - [FEATURE]Add 'trim' PPL command #427)
• - position - [FEATURE]Add PPL position command #424
• - substring - [FEATURE]Add substring PPL command #426
• - upper - [FEATURE]Add upper PPL command  #428
• Add PPL Grok command #451

Arithmetic Aggregation Commands

• - mode #452
• - median #453
• - WindowFunction #454

Arithmetic Math Commands

• - abs #455
• - ceil #456
• - floor #457
• - log #458
• - sqrt #459
• - ln #472
• Missing PPL command - exp #471
• - pi #470
• - pow #469
• - round #468
• - signum #467
• - mod #466
• - rand #465
• - sign #464

Other Commands

• - eval -[FEATURE]Add eval PPL command #429
• - RareTopN #460
• [FEATURE] add Rare PPL command #461
• Add PPL Patterns command #462
• Missing PPL command - Interval #463

---

Do you have any additional context?

https://github.com/opensearch-project/sql/blob/main/docs/user/ppl/index.rst

SQL

• [BUG] SELECT, WHERE, and GROUP BY on geo_point, ip, ranges, shape, and knn_vector sql#1781
• Design for LIMIT in pagination. sql#1752
• [FEATURE] Materialized views (aka virtual indexes) on object stores sql#1080
• [FEATURE] Support for subqueries or chaining of queries sql#1441
• [FEATURE] Support join functionality for trace-analytics use case sql#892
• [FEATURE]Prepared Statement Like API sql#1519
• [FEATURE] PPL LOOKUP Functionality sql#2651

Spark

• Ppl spark join command #69
• https://github.com/opensearch-project/opensearch-spark/blob/main/docs/PPL-on-Spark.md
• https://github.com/opensearch-project/opensearch-spark/tree/main/ppl-spark-integration

---