Switch to isoelectronic valence model (#7491)

* change valence model to use isolobal analogy

Remove support for five-coordinate C+ and, by analogy, five-coordinate N+2

Removes support for charge states that take atoms past the end of the periodic table
  i.e. [Lv-4] is no longer supported

* update the tests for that

* remove valence state of 6 for Al

* fix representation of phosphate in the mol2 parser

this is a correction of what was done during #5973

* cleanup the exceptions for P, S, As, and Se

* drop valence states:

Si 6, P 7, As 7

* a couple of additional changes from #7397

* update java tests

* fix an inconsistency: Rb now supports valence -1

* documentation

* - replace operator[] with at() for bounds check
- extract some code into a function to avoid duplication
- use TAB as separator throughout in the periodic table data for consistency

* removing the .at() usage

We know that these vectors aren't empty, so there's no need for the bounds check.

---------

Co-authored-by: ptosco <paolo.tosco@novartis.com>

Code/JavaWrappers/gmwrapper/src-test/org/RDKit/AromaticTests.java

@@ -50,6 +50,7 @@ public class AromaticTests extends GraphMolTest {
 	@Test
 	public void testNCIAromaticRegression() throws Exception {
 		String filePath = getFilePath("NCI_aromat_regress.txt");
+		// assertEquals(filePath,"foo");
 		performAromaticTest(filePath,0);
 	}
 

Code/JavaWrappers/gmwrapper/src-test/org/RDKit/SmilesDetailsTests.java

@@ -980,8 +980,9 @@ public class SmilesDetailsTests extends GraphMolTest {
 		Bond bond;
 		String smi;
 
+
 		smi = "C1CC[C+]1=1CCC1";
-		mol = RWMol.MolFromSmiles(smi);
+		mol = RWMol.MolFromSmiles(smi, 0, false);
 		assertNotNull(mol);
 		bond = mol.getBondBetweenAtoms(3, 0);
 		assertNotNull(bond);
@@ -991,7 +992,7 @@ public class SmilesDetailsTests extends GraphMolTest {
 		assertEquals(Bond.BondType.DOUBLE, bond.getBondType());
 
 		smi = "C1CC[C+]=11CCC1";
-		mol = RWMol.MolFromSmiles(smi);
+		mol = RWMol.MolFromSmiles(smi, 0, false);
 		assertNotNull(mol);
 		bond = mol.getBondBetweenAtoms(3, 0);
 		assertNotNull(bond);

Code/JavaWrappers/gmwrapper/src-test/org/RDKit/SmilesTests.java

@@ -87,8 +87,8 @@ public class SmilesTests extends GraphMolTest {
 	// testing molecules which have been problematic
 	@Test
 	public void testProblems() {
-		testSpellings("[Al+3]CCC",
-				new String[] { "CCC[Al+3]", "C(C)(C[Al+3])"});
+		testSpellings("[Al+2]CCC",
+				new String[] { "CCC[Al+2]", "C(C)(C[Al+2])"});
 		testSpellings("C(=O)(Cl)CC(=O)Cl", 
 				new String[] { "ClC(CC(Cl)=O)=O", "C(Cl)(=O)CC(=O)Cl","C(Cl)(=O)CC(Cl)=O"});
 		testSpellings("C(=O)(Cl)c1ccc(C(=O)Cl)cc1",