Create a contributor section in the RTEMS Documentation.

Summary

We need to have a giant list of those who have contributed to RTEMS like most projects maintain. We have some users in the RTEMS MAINTAINERS file plus many more that have contributed but are listed nowhere.

It would be great to have this for %6.1 so it makes it into the release we can take it from the commit history in Git.

Here is the old MAINTAINERS file:

• https://gitlab.rtems.org/rtems/rtos/rtems/-/blob/9dce0426d42adac532a3610e899e9d6665755d77/MAINTAINERS

This file will need to be included here as well:

• https://gitlab.rtems.org/rtems/rtos/rtems/-/blob/807070a696a93c1dae09f527efd2a516b01d7277/c/ACKNOWLEDGEMENTS