API sanation for state types

[dr-orlovsky]

• Add blinding to data types
• Make function names and signatures working with blinding factors more consistent
• Separate state which contains blinding information from the state which doesn't
• Provide a trait for non-blinded state (KnownState)

Prerequisite for https://github.com/RGB-WG/rgb-std/pull/126 and https://github.com/RGB-WG/rgb/pull/92

[codecov[bot]]

Codecov Report

Attention: 73 lines in your changes are missing coverage. Please review.

Comparison is base (c627404) 16.9% compared to head (2b59903) 16.7%.

Files	Patch %	Lines
src/contract/data.rs	9.1%	30 Missing :warning:
src/contract/contract.rs	4.2%	23 Missing :warning:
src/contract/attachment.rs	0.0%	13 Missing :warning:
src/vm/op_contract.rs	0.0%	5 Missing :warning:
src/validation/logic.rs	0.0%	1 Missing :warning:
src/validation/state.rs	0.0%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #200 +/- ## ======================================== - Coverage 16.9% 16.7% -0.2% ======================================== Files 32 32 Lines 3827 3874 +47 ======================================== - Hits 647 646 -1 - Misses 3180 3228 +48 ``` | [Flag](https://app.codecov.io/gh/RGB-WG/rgb-core/pull/200/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RGB-WG) | Coverage Δ | | |---|---|---| | [rust](https://app.codecov.io/gh/RGB-WG/rgb-core/pull/200/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RGB-WG) | `16.7% <12.0%> (-0.2%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RGB-WG#carryforward-flags-in-the-pull-request-comment) to find out more.

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