Update core dep resolution functionality to use poetry compat checks

Remove custom package compatibility checks
Add checks using poetry's built in package compatibility checking using markers
Update venv integration to use poetry's venv processing tools
Remove unused constants

tox_poetry_installer/installer.py

@@ -3,7 +3,6 @@
 # See the docstring in 'tox_poetry_installer._poetry' for more context.
 # pylint: disable=import-outside-toplevel
 import typing
-from pathlib import Path
 from typing import Sequence
 from typing import Set
 
@@ -12,6 +11,7 @@ from poetry.core.packages import Package as PoetryPackage
 from tox.venv import VirtualEnv as ToxVirtualEnv
 
 from tox_poetry_installer import constants
+from tox_poetry_installer import utilities
 
 if typing.TYPE_CHECKING:
     from tox_poetry_installer import _poetry
@@ -33,7 +33,7 @@ def install(
     )
 
     pip = _poetry.PipInstaller(
-        env=_poetry.VirtualEnv(path=Path(venv.envconfig.envdir)),
+        env=utilities.convert_virtualenv(venv),
         io=_poetry.NullIO(),
         pool=poetry.pool,
     )
@@ -49,5 +49,5 @@ def install(
             installed.add(dependency)
         else:
             tox.reporter.verbosity2(
-                f"{constants.REPORTER_PREFIX} Already installed {dependency}, skipping"
+                f"{constants.REPORTER_PREFIX} Skipping {dependency}, already installed"
             )