Draft: Docs: Add environment variable reference page

[adeljo-amd]

This is part of the environment variable initiative, where we aim to create a ROCm environment variable index page that contains the links to every component's environment variable page. I extracted the environment variables from the source code, but had to guess a lot of the values and purposes of the variables.

It would be great to get feedback on what the expected values are (of if there are default values for some), and whether the environment variables listed in the page are important for the users.

[kiritigowda]

@adeljo-amd - please review this develop help page and let me know if this covers all the variables - https://github.com/ROCm/MIVisionX/wiki/Developer-Tools:-OpenVX

[adeljo-amd]

@adeljo-amd - please review this develop help page and let me know if this covers all the variables - https://github.com/ROCm/MIVisionX/wiki/Developer-Tools:-OpenVX

Thanks for this, I've updated the reference page based on these (I did not include the MIOpen environment variables or build-related environment variables). Let me know if the reference page looks better now

[adeljo-amd]

@kiritigowda Sorry, I did not realise this was marked as draft when it was ready all this time - is there any other feedback concerning the environment variables listed here?