Update versions in README for 2.9.

Fedora is now at version 35 and Debian at version 11.

Move basic.robot to tests directory.

Create new directory 'robot/tests' for all the Robot Framework tests
and move the existing tests there.

Then we can run the tests with command 'robot tests'.

Move robot test executables to bin dir.

Move the test executables generated for the Robot Framework
tests to the robot/test_sources/bin directory.

Mention Git mirrors in README.md.

Change gnat-8 to gnat-10 in debian/stable build setup.

Sourcehut updated their debian/stable to bullseye,
which has gnat-10 package instead of gnat-8.

Add .editorconfig file.

Ada files use 3 spaces, Makefile tabs,
unix style newlines.

Mention SPDX identifier addition in NEWS.txt.

Don't mention Fedora version in install instructions

Increase version to 2.9 in NEWS.txt.

While there, mention the Alire package manager configuration
files from Michael Rohan.

Increase version to 2.9 everywhere.

As done with Alire project file, increate the version to 2.9
in the documentation and Linux (Fedora) GNAT project files.

Increase Library_Version to 2.9.0 in ahven_alire.gpr.

Merge heads.

Specify Library_Interface in ahven_alire projet file.

As we have some extra files in src directory, specify
the ones we actually use to avoid unnecessary compilations.

Eliminate parameter Severity from Report_Not_Ok function.

This allows us to get rid of one GNAT warning about
unused parameter.

Add Alire packaging support files

Added the top level alire.toml file to define Ahven as an Alire package
and the gnat/ahven_alire.gpr project file to build the library using the
defaults generated by Alire (style checks are disabled by default).

Improve control/tap/tester.pl a little.

Add ability to give the test runner as an argument.
Also do some sanity checks and return status based
on the test execution status.

Remove extra Test_Class_Wrapper record from Ahven.Framework.

The Test_Class_Wrapper was added as a work-around for some old
Janus/Ada bugs. The latest version of Janus/Ada no longer
needs the work-around so we can drop it.

Rename the procedure inside ahven_libmain.adb.

Rename libmain.adb to ahven_libmain.adb.

As someone might use multiple libraries, which all might have
their own libmain.adb, rename libmain.adb to ahven_libmain.adb.

This way our main file, which lists the dependencies for the library,
is more or less unique and doesn't conflict with other libmain.adb
files.

Add SPDX license identifier to fail1.adb also.

Oops, missed one file from the first go.