Update dependencies to a post-Dagster world

Spine Engine doesn't use Dagster anymore, so we need not restrict
spinedb_api dependencies anymore.

Also, removed requirements.txt files in favor of pyproject.toml.
Developer and documentation dependencies can now be installed
by specifying the [dev] tag when telling Pip to install this
package, i.e.

python -mpip install -e .[dev]

Re spine-tools/Spine-Toolbox#2522

README.md

@@ -36,21 +36,19 @@ To install the latest development version use the Git repository url:
 ## Building the documentation
 
 Source files for the documentation can be found in `docs/source` directory. In order to 
-build the HTML docs, you need to install the additional documentation building requirements
+build the HTML docs, you need to install the developer dependencies
 by running:
 
-    $ pip install -r dev-requirements.txt 
+    $ pip install -e .[dev]
 
 This installs Sphinx (among other things), which is required in building the documentation.
 When Sphinx is installed, you can build the HTML pages from the source files by running:
 
-    > docs\make.bat html
+    > bin\build_doc.bat
 
 or
 
-    $ pushd docs
-    $ make html
-    $ popd
+    $ bin/build_doc.py
 
 depending on your operating system.        
 

docs/source/conf.py

@@ -281,7 +281,10 @@ def setup(sphinx):
 # -- Options for intersphinx extension ---------------------------------------
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {"https://docs.python.org/": None, "https://docs.sqlalchemy.org/en/13/": None}
+intersphinx_mapping = {
+    "python": ("https://docs.python.org/", None),
+    "sqlalchemy": ("https://docs.sqlalchemy.org/en/13/", None)
+}
 
 # -- Options for todo extension ----------------------------------------------
 

pyproject.toml

@@ -16,10 +16,8 @@ dependencies = [
     # v1.4 does not pass tests
     "sqlalchemy >=1.3, <1.4",
     "alembic >=1.7",
-    "faker >=8.1.2",
     "datapackage >=1.15.2",
     "python-dateutil >=2.8.1",
-    # v1.22 requires Python 3.8 or later
     "numpy >=1.20.2",
     "scipy >=1.7.1",
     "openpyxl >=3.0.7, !=3.1.1",
@@ -34,7 +32,15 @@ dependencies = [
 Repository = "https://github.com/spine-tools/Spine-Database-API"
 
 [project.optional-dependencies]
-dev = ["coverage[toml]", "pyperf"]
+dev = [
+    "coverage[toml]",
+    "pyperf",
+    "sphinx",
+    "sphinx-autoapi",
+    "sphinx_rtd_theme",
+    "recommonmark",
+    "black == 21.12b0"
+]
 
 [build-system]
 requires = ["setuptools>=64", "setuptools_scm[toml]>=6.2", "wheel", "build"]