Resolve an assortment of infrastructure errors - pkg_resources and GAMS

[mrmundt]

Fixes NA

Summary/Motivation:

We have lots of new deprecation warnings showing up in the book examples because the pyomo_main script uses pkg_resources.

Changes proposed in this PR:

• Replace pkg_resources with importlib.metadata
• Turn off GAMS until we can figure out a new licensing plan

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[jsiirola]

In addition, this PR is missing pkg_resources in 2 other places:

diff --git a/pyomo/contrib/appsi/solvers/maingo.py b/pyomo/contrib/appsi/solvers/maingo.py
index 8273061be..94d18cc26 100644
--- a/pyomo/contrib/appsi/solvers/maingo.py
+++ b/pyomo/contrib/appsi/solvers/maingo.py
@@ -173,11 +173,15 @@ class MAiNGO(PersistentBase, PersistentSolver):
         return self._available

     def version(self):
-        import pkg_resources
+        import importlib.metadata

-        version = pkg_resources.get_distribution('maingopy').version
-
-        return tuple(int(k) for k in version.split('.'))
+        version = importlib.metadata.version('maingopy').split('.')
+        for i, n in enumerate(version):
+            try:
+                version[i] = int(version[i])
+            except:
+                pass
+        return tuple(version)

     @property
     def config(self) -> MAiNGOConfig:

and

diff --git a/pyomo/common/dependencies.py b/pyomo/common/dependencies.py
index a2cf06fbb..a68c1797b 100644
--- a/pyomo/common/dependencies.py
+++ b/pyomo/common/dependencies.py
@@ -449,10 +449,22 @@ def check_min_version(module, min_version):

             _parser = _version.parse
         except ImportError:
-            # pkg_resources is an order of magnitude slower to import than
-            # packaging.  Only use it if the preferred (but optional)
-            # packaging library is not present
-            from pkg_resources import parse_version as _parser
+            try:
+                # pkg_resources is an order of magnitude slower to import than
+                # packaging.  Only use it if the preferred (but optional)
+                # packaging library is not present
+                from pkg_resources import parse_version as _parser
+            except ImportError:
+                # This parser is NOT complient with PEP 440, but will be
+                # OK in 99% of the use cases.
+                def _parser(verstr):
+                    version = verstr.split('.')
+                    for i, v in enumerate(version):
+                        try:
+                            version[i] = int(v)
+                        except:
+                            pass
+                    return tuple(version)
         check_min_version._parser = _parser
     else:
         _parser = check_min_version._parser