apidom-reference: caching strategy for OpenAPI 3.1.0 dereferencing

[char0n]

Implementing effective caching strategy consist of two things

• implementing caching strategy for uri selector
• implementing caching strategy for `$anchor selector

Note that uri selector internally uses $anchor selector if URI is accompanied with hash segment.

Originally reported as performance regression in swagger-api/swagger-ui#8606

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I've drop requirement for implementing caching strategy for `$anchor selector

[char0n]

uri selector

Before optimization: 1,583 ops/sec ±2.95% (671 runs sampled)
After optimization: 1,756 ops/sec ±2.06% (673 runs sampled)