Rename mirage to fair

[dmytrotkk]

This pull request introduces significant changes to replace the "Mirage" build type with a new "Fair" build type across the codebase, documentation, and workflows. The changes include renaming files and functions, updating scripts and workflows, and modifying documentation to reflect the new "Fair" terminology.

Transition from "Mirage" to "Fair":

Workflow Updates:

• .github/workflows/publish.yml: Replaced "mirage" and "mirage-" branches with "fair" and "fair-" branches in the workflow triggers. Updated the build_type matrix to replace "mirage" with "fair". [1] [2]
• .github/workflows/test.yml: Updated all references to "mirage" in build and test commands to "fair". Adjusted scripts to use bash explicitly for execution. [1] [2] [3]

Documentation Updates:

• README.md: Replaced all mentions of "Mirage" with "Fair" in descriptions, examples, and commands. Updated sections, commands, and environment variables to reflect the new "Fair" build type. [1] [2] [3] [4] [5] [6] [7]

Codebase Updates:

• Renamed files:
  • node_cli/cli/mirage_boot.py → node_cli/cli/fair_boot.py
  • node_cli/cli/mirage_node.py → node_cli/cli/fair_node.py
• Updated function names, CLI commands, and help text to replace "mirage" with "fair". [1] [2] [3] [4]

Submodule Update:

• helper-scripts: Updated the submodule to a new commit.

These changes ensure consistency in the transition from "Mirage" to "Fair" across the project, including workflows, documentation, and the codebase.