experiment with multilevel inheritance model

[qalisander]

Changes in this approach based upon this improvement to the stylus sdk.
This pr missing documentation. Since it is just an example of how contracts can override internal function of the other contract with a help of #[r#virtual] and #[r#override] proc macros. Matching solidity implementation a bit closer then before.

[netlify]

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🔨 Latest commit	cdf82e3
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[codecov]

Codecov Report

Attention: Patch coverage is 89.46850% with 107 lines in your changes missing coverage. Please review.

Project coverage is 89.9%. Comparing base (7694478) to head (cdf82e3).
Report is 37 commits behind head on main.

Files with missing lines	Patch %	Lines
contracts-proc/src/virtual.rs	82.4%	33 Missing ⚠️
...ntracts/src/token/erc721/extensions/uri_storage.rs	18.5%	22 Missing ⚠️
...ontracts/src/token/erc721/extensions/enumerable.rs	92.1%	15 Missing ⚠️
contracts/src/token/erc721/extensions/pausable.rs	83.8%	10 Missing ⚠️
contracts/src/token/erc721/mod.rs	97.7%	10 Missing ⚠️
contracts-proc/src/lib.rs	66.6%	9 Missing ⚠️
contracts/src/token/erc721/extensions/burnable.rs	90.5%	8 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
contracts/src/utils/pausable.rs	82.9% <100.0%> (+1.7%)	⬆️
contracts/src/token/erc721/extensions/burnable.rs	95.6% <90.5%> (-4.4%)	⬇️
contracts-proc/src/lib.rs	66.6% <66.6%> (ø)
contracts/src/token/erc721/extensions/pausable.rs	83.8% <83.8%> (ø)
contracts/src/token/erc721/mod.rs	95.9% <97.7%> (-0.2%)	⬇️
...ontracts/src/token/erc721/extensions/enumerable.rs	88.6% <92.1%> (+1.0%)	⬆️
...ntracts/src/token/erc721/extensions/uri_storage.rs	60.8% <18.5%> (-24.1%)	⬇️
contracts-proc/src/virtual.rs	82.4% <82.4%> (ø)