Fix bops calculation

[irenaby]

Pull Request Description:

Support for bops computation on virtual nodes in RU calculator.
Updated virtual graph substitutions to fix activation & weights RU calculation on virtual graph.
Use RU calculator for bops in mixed precision search.
Added integration tests for RU calculator (framework -> graph preparation -> RU calculator, original vs virtual graph).
Added verification that target RU is satisfied by final RU in MP tests.

Checklist before requesting a review:

• I set the appropriate labels on the pull request.
• I have added/updated the release note draft (if necessary).
• I have updated the documentation to reflect my changes (if necessary).
• All function and files are well documented.
• All function and classes have type hints.
• There is a licenses in all file.
• The function and variable names are informative.
• I have checked for code duplications.
• I have added new unittest (if necessary).

[ofirgo]

@irenaby
I don't remember from all we discussed whether this PR changes any behavior that is not BOPs only related (activation/weights memory estimation, any RU computation in MP or RU data besides BOPs).
If there is something like that, please specify this in the PR description.