v3.0.0: Switch to using of external contracts

Main updates

• Use aeliot/env-resolver to resolve env variables #244
• Refactor registrars to reduce copy-paste, extend config overriding and validation #248, #250
• Color generator for labels #252

Backward Compatibility Breaks

• Switch to using of external contracts aeliot/todo-registrar-contracts #239
• Remove deprecated general config DTOs #243
• Cleanup code (make classes final & readonly) #251

Minors

• Mark deprecations & internal services #241
• Refactor getting of registrar #242
• Refactor reading of config #253
• Create functional tests #245
• Move scripts to dotted directory #254
• Simplify TODO registrar workflow with new action #267
• Update documentation #247, #257

Full Changelog: v2.3.1...v3.0.0