[Spec][Ref][CPU] Improve Inverse testing suite, add LU pseudocode to specification

[PiotrKrzem]

Details:

• Improved Inverse testing suite for dynamic shapes in the CPU plugin
• Introduced random tests to PT FE Inerse testing suite
• Added LU decomposition pseudocode to spec
• Removed numpy import from opset/opset14.py
• Moved reference inverse outside inverse namespace and removed inverse namespace
• Added label propagation tests
• Changed bf16 threshold restriction
• Removed dynamic rank check as it's already present in CPU plugin
• Simplified check for B => P[i] == j
• Did NOT use std::copy_n as ov::bfloat16 is missing difference_value to use in std implementations

Tickets:

• 133090