This ticket cleans up how the contents of src/bin are installed. One of its goals is to make the sagelib installation done by src/setup.py self-contained regarding the scripts that it needs at runtime.

Previous tickets moved some of the scripts to build/bin (no longer installed in SAGE_LOCAL).

In follow-up tickets, src/bin could be cleaned up more.

• See the list of files added on this ticket to src/setup.py for beginnings of a categorization.
• Install sage-env-config as part of sage_conf #29850: Install src/bin/sage-env-config as part of sage_conf
• Install sage_setup with setuptools as a prerequisite for building/installing sagelib #29847: Install sage_setup with setuptools as a prerequisite for building/installing sagelib, install sage-the-distribution scripts as "scripts"

Depends on #29111

CC: @jdemeyer @vbraun @embray @isuruf @jhpalmieri @kiwifb @kcrisman @orlitzky @antonio-rojas @dimpase

Component: build

Author: Matthias Koeppe

Branch/Commit: 19d7f67

Reviewer: John Palmieri, François Bissey

Issue created by migration from https://trac.sagemath.org/ticket/21559