Update Docs Page March 2025

[Bill-Becker]

This pull request includes several documentation improvements and updates to the REopt package, focusing on setup instructions, solver usage, and input formats. The most important changes include updating the setup instructions to use the HiGHS solver, modifying the Project.toml file for Julia compatibility, and refining the documentation for better clarity and accuracy.

Documentation improvements:

• docs/src/index.md: Updated installation instructions to include the HiGHS solver and clarified the process for adding the GhpGhx.jl package. [1] [2]
• docs/src/reopt/examples.md: Revised examples to use the HiGHS solver and provided additional details on the input file and solver settings. [1] [2]
• docs/src/reopt/inputs.md: Enhanced descriptions of input formats and added documentation for CoolingLoad. [1] [2]

Compatibility updates:

• docs/Project.toml: Adjusted Julia compatibility to support all versions starting from 1.0.

General fixes:

• CHANGELOG.md: Added a new section for the development version and documented updates to the docs pages.
• Various files: Standardized the environment activation command in multiple documentation files. [1] [2]