Provide embedded compiled NeoFS contracts

[cthulhu-rider]

isolated changes from #2301. Starting from this, I'll try introduce changes partially to lighten review process

note that these changes do not yet present the script for compiling and copying contract files into contracts dir, suggestions are welcome

in contrast to the proposed option for naming files in #2195, i decided not to name files with serial numbers because to me it's clearer to see what contract is represented by particular files. Anyway, this pattern can be changed at any time

[codecov]

Codecov Report

Merging #2391 (8d48fb6) into master (93733ff) will increase coverage by 0.10%.
The diff coverage is 82.25%.

❗ Current head 8d48fb6 differs from pull request most recent head 54874e4. Consider uploading reports for the commit 54874e4 to get more accurate results

@@            Coverage Diff             @@
##           master    #2391      +/-   ##
==========================================
+ Coverage   30.03%   30.14%   +0.10%     
==========================================
  Files         398      399       +1     
  Lines       29806    29868      +62     
==========================================
+ Hits         8953     9004      +51     
- Misses      20128    20134       +6     
- Partials      725      730       +5     

Impacted Files	Coverage Δ
contracts/contracts.go	82.25% <82.25%> (ø)

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[roman-khimov]

You can name them like 01-alphabet, 20-netmap, etc. But it's important since you can easily see the deployment sequence, you can make the code more generic (especially with reduced number of deployment parameters) and you can more easily stuff some new contract into the mix.

[roman-khimov]

The only reason for not doing so, btw, is storing contracts in neofs-contract and getting them right from that repo. This in fact can be done with a simple wrapper that would make a proper Go package out of these files.

[cthulhu-rider]

@roman-khimov moved to NN.nef + NN.manifest.json naming pattern, check

for now added NNS contract only just to prevent go:embed directive failure