1736 add blockchain cli tools

[jasperpotts]

PR for work on command line tools for processing record file history.

This pull request introduces several documentation improvements and project configuration updates, focusing on clearer build instructions, coding conventions, and more accurate references to the tools module. It also adds new experimental protobuf definitions for block streaming and proof structures.

Documentation and Reference Improvements:

• Added a comprehensive BUILDING.md file at the project root, detailing prerequisites, common build tasks, and module-specific instructions for building and running each app/module.
• Updated references to the tools module in README.md and docs/overview.md to use correct relative links, improving navigation and accuracy. [1] [2]
• Removed outdated or redundant documentation files in docs/tools/, including README.md and quickstart.md, streamlining and centralizing documentation. [1] [2]

Project Configuration and Coding Standards:

• Added .github/copilot-instructions.md to provide explicit, actionable guidance for Copilot-generated Java code, covering file headers, import ordering, Javadoc, naming conventions, formatting, logging, tests, and usage of modern Java APIs.
• Updated .editorconfig to set the default indentation size to 4 spaces, aligning with the documented coding standards.

Protobuf Definitions for Experimental Block Streaming:

• Added experimental_block.proto defining the Block message, with detailed comments on block structure, usage, and RFC keyword interpretation.
• Added experimental_block_footer.proto defining the BlockFooter message, describing root hashes for block verification and state, with RFC-style documentation.