[SYCL] Implement eviction in persistent cache

[uditagarwal97]

This PR implements eviction for persistent cache.
Eviction is disabled by default and can be controlled by the user via SYCL_CACHE_MAX_SIZE variable.

Here's how eviction works:

1. File size: A file called, cache_size.txt, is stored at the root of persistent cache. Every time a process adds a new entry to cache, it will also update the cache_size.txt file. This file is used to track the size of persistent cache. For backwards compatibility, if SYCL RT does not find cache_size.txt in the cache root, it will create once. All access to cache_size.txt are done using LockCacheItem, to prevent data races.
2. When adding a new entry to cache, SYCL RT will check the cache_size.txt file and if the cache size exceeds the threshold, eviction is triggered.
3. During eviction, SYCL RT will determine the last access time of each cache entry (using POSIX's stat or Window's GetFileAttribute). Items are evicted based on the LRU policy.