update on compiler to install requirements.txt automatically

[AminTorabi-NOAA]

This PR is an update on compiler.sh script to automatically install the requirements from requirements.txt before running the compilation steps.
It add the pip install -r requirements.txt command at the beginning of the script.
It check if the requirements file exists: It's a good practice to check if the requirements.txt file exists before attempting to install.

Additions

Removals

Changes

Testing

1. Made a new environment, clone t-route, and install it successfully with updated compiler.

Screenshots

Notes

Todos

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows project standards (link if applicable)
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Visually tested in supported browsers and devices (see checklist below 👇)
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️

Testing checklist

Target Environment support

• Windows
• Linux
• Browser

Accessibility

• Keyboard friendly
• Screen reader friendly

Other

• Is useable without CSS
• Is useable without JS
• Flexible from small to large screens
• No linting errors or warnings
• JavaScript tests are passing