Add name converters between Generic converters

[AlexSkrypnyk]

Add methods for all Generic conversions (42 in total).

The converters are NOT strict. This means, that ::strict() should not be used.

Here is the table with the conversion names and corresponding numbers:

Number	Conversion Name
1	snake2camel
2	snake2pascal
3	snake2kebab
4	snake2train
5	snake2flat
6	snake2cobol
7	camel2snake
8	camel2pascal
9	camel2kebab
10	camel2train
11	camel2flat
12	camel2cobol
13	pascal2snake
14	pascal2camel
15	pascal2kebab
16	pascal2train
17	pascal2flat
18	pascal2cobol
19	kebab2snake
20	kebab2camel
21	kebab2pascal
22	kebab2train
23	kebab2flat
24	kebab2cobol
25	train2snake
26	train2camel
27	train2pascal
28	train2kebab
29	train2flat
30	train2cobol
31	flat2snake
32	flat2camel
33	flat2pascal
34	flat2kebab
35	flat2train
36	flat2cobol
37	cobol2snake
38	cobol2camel
39	cobol2pascal
40	cobol2kebab
41	cobol2train
42	cobol2flat

Add these converters after public static function flat(string $string): string {

Use the same format to test

/**
 * @from I-Am-A--String-With-Sp@ce¥s-14-And-😀-Unicode-Élève
 * @to i_am_a__string_with_sp@ce¥s_14_and_😀_unicode_élève
 */
 public static function train2snake(string $string): string {
  // code here
 }