Reach out to ("silent") users of ORT to ask for permission to use their logos

[sschuberth]

We should include some nice company logos to ORT's README.md to show off who's already using ORT, also to make us more attractive to more users.

[sschuberth]

This has been partly addressed with the introduction of ADOPTERS.md where contributors can add their own logos. We should still encourage contributors to actually do so, e.g. by adding a note to the pull request template, and leading by example for the companies the TSC members are working for.