Software requirements: Semaphore: collected all requirements so far

[stanislaw]

As discussed on the meeting last week, I would like to open this combined PR for review.

The contents:

• Requirements from https://github.com/zephyrproject-rtos/reqmgmt/pull/30 by @nashif. Note that all requirements have been preserved.
• Requirements from https://github.com/zephyrproject-rtos/reqmgmt/pull/31 by @legrand-gregshue.
• Requirements from @legrand-gregshue and @stanislaw brainstorming sessions.
• Some requirements were duplicates. I have merged them where appropriate, and these requirements now contain more than one alternatives separated by a horizontal line ----. Let's pick the wording that works best.

Some notes:

• Note that due to the recent merges I could not preserve the original commits of both @nashif and @legrand-gregshue. Instead, it is just one commit by @stanislaw. Hopefully it is not too big of an issue.
• To prevent merge conflicts with the fragments PRs that Greg has been creating, I am adding this fragment to be the last one in the software requirements index.sdoc.

[stanislaw]

As discussed at the SWG meeting 02.05.2024, this PR is being closed. The only source of truth for the new semaphore requirements is: https://github.com/zephyrproject-rtos/reqmgmt/pull/30.