rewrite the project as a static site generator

this removes Flask, reworks a number of library methods accordingly, and
adds generators and build commands to process the instance directory
(largely unchanged, except config.py is now config.json) and spit out
files suitable to be served by a web server such as Nginx.

there are probably some rough edges here, but overall this works.

also note, as this is no longer server software on a network, the
license has changed from AGPLv3 to GPLv3, and the "or any later version"
allowance has been removed

Signed-off-by: Brian S. Stephan <bss@incorporeal.org>

tests/test_commands.py

@@ -0,0 +1,30 @@
+"""Test command line invocations.
+
+SPDX-FileCopyrightText: © 2023 Brian S. Stephan <bss@incorporeal.org>
+SPDX-License-Identifier: GPL-3.0-only
+"""
+import os
+import tempfile
+from subprocess import run
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+
+
+def test_build():
+    """Test some of the output of the core builder command."""
+    with tempfile.TemporaryDirectory() as tmpdir:
+        result = run(['incorporealcms-build', os.path.join(HERE, 'instance'), tmpdir],
+                     capture_output=True, encoding='utf8')
+        assert "creating temporary directory" in result.stdout
+        assert "copying file" in result.stdout
+        assert "creating symlink" in result.stdout
+        assert "creating directory" in result.stdout
+        assert "renaming" in result.stdout
+
+
+def test_build_error():
+    """Test some of the output of the core builder command."""
+    result = run(['incorporealcms-build', os.path.join(HERE, 'instance'), os.path.join(HERE, 'test_markdown.py')],
+                 capture_output=True, encoding='utf8')
+    assert "specified output path" in result.stderr
+    assert "exists as a file!" in result.stderr