Parent ticket - WT-13599

As we progress with eviction modularising, it's been found that separating eviction into it's own struct is crucial for defining it's clear boundary.  

Currently, cache metadata, cache pool and eviction are usually defined within a single struct and are configured, created, and destroyed using the same functions. However, based on the boundaries defined in the 1.1 doc. It is evident that eviction, in terms of its functionality, should be distinct from cache metadata and cache pool. Therefore, the foundational step is to separate eviction-related components. 

A POC has been created here, it was quite straightforward to do so.

Scope -

• Seperate all eviction related fields, structs, macros.