Feature/running inside bash

[memsharded]

Changelog: Feature: New tools.microsoft.bash:active conf to indicate already running inside bash (but not targeting subsystem) Docs: https://github.com/conan-io/docs/pull/XXXX

AFTER https://github.com/conan-io/conan/pull/11061

Close https://github.com/conan-io/conan/issues/10900

Open issues:

• We don't want to run inside "bash", so we need to make sure run_in_windows_bash() is not being triggered
• At the moment it requires defining the win_bash=True in the recipe, probably shouldn't be necessary. Actually the win_bash=True in recipes I find it a bit confusing every time I work on this. In this case, it will probably fir the run_in_windows_bash()
• This is very difficult to test, as it would mean running the test from bash already, doesn't seem possible in the test suite.