Significant additions, better introduction and grouping improvements

Added

• IAM, Authentication and Authorization; under Security
• Language-theory knowledge, under a new "Other general technical knowledge" section (includes regex)
• Stack vs Heap, under Data Structures
• Non-relational databases, under back-end development
• Message brokers, under back-end development
• Pagination, under front-end development
• Cryptographic protocols (TLS, SSL), in Security
• Relevant internet protocols, in Architecture
• Service Mesh, in Architecture
• Data modeling, in Architecture
• Processes vs Threads, under Infrastructure
• Web servers and reverse proxies, under Infrastructure
• Monitoring and Observability, under Infrastructure
• Immutability, in Functional Programming, within Principles
• Client-side rendering (CSR) vs server-side rendering (SSR), in front-end development
• Browser events, under front-end development
• Profiling, under Optimization
• Artifact repositories and image registries, in DevOps practices

Changed

• Improved introduction to better reflect the importance of evergreen skills and portable technical knowledge
• Improved license note
• Grouped the "be rational and facts-based" entry into Critical Thinking, with link to its definition
• Renamed "master-slave" to "Controller-agent / Primary-replica"
• Improved Peer Code Review best practice adding TL;DR note
• Links for "control structures" and "boolean algebra"
• Further clarifications in Clean Code section
• Split Architecture and Infrastructure
• Monolith vs Microservices, in Architecture
• Concurrency is now part of "Other general technical knowledge"
• Replaced "system tests" with "end-to-end tests"

Removed

• Scaling and optimization section. Optimization is now under "Other general technical knowledge" and the scaling-related bullets are part of Infrastructure