Tracking materials to gather into this text

[dr-orlovsky]

• https://github.com/RGB-WG/rgb-node/discussions/218
• https://github.com/RGB-WG/rgb-node/discussions/219
• RGB Node contract state API rgb-node#228
• https://github.com/RGB-WG/rgb-node/discussions/220
• https://github.com/orgs/LNP-BP/discussions/132
• https://github.com/orgs/LNP-BP/discussions/122
• https://github.com/RGB-WG/contractum.org
• https://github.com/RGB-WG/rgb-node/discussions/243
• Basics of languague design contractum-lang#1