Refactor Builder

- Rename `getClassName()` to `getService()`
- Replace overloaded methods with declared ones:
  - `build()`
  - `resolve()`
  - `get()`
  - `isset()`
  - `go()`
- Split `HasBuilder` **interface** into `ReturnsBuilder`,
  `ResolvesBuilder` and others
- Add `HasBuilder` **trait** to simplify builder servicing
- Update "lk-util generate builder" command
  - Allow properties to be excluded from "lk-util generate builder"
    output
  - Allow methods to be forwarded from a builder to a new instance
    without calling `$builder->go()` first
- Rename `Builder::get()` to `getB()` and `isset()` to `issetB()` so
  instance methods with these names can be surfaced
- Adopt method forwarding for `CurlerBuilder`

Also:
- Make both callbacks in `IFluentInterface::if()` optional

[no ci]

Author: lkrms

lib/lk-util/Command/Generate/Concept/GenerateCommand.php

@@ -36,8 +36,7 @@ abstract class GenerateCommand extends Command
     protected const VISIBILITY_PUBLIC = 'public';
     protected const VISIBILITY_PROTECTED = 'protected';
     protected const VISIBILITY_PRIVATE = 'private';
-
-    private const TAB = '    ';
+    protected const TAB = '    ';
 
     protected ?string $OutputDescription;
     protected ?bool $ToStdout;
@@ -482,11 +481,12 @@ protected function generateGetter(
         string $name,
         string $valueCode,
         $phpDoc = '@internal',
-        string $returnType = 'string'
+        string $returnType = 'string',
+        string $visibility = GenerateCommand::VISIBILITY_PROTECTED
     ): array {
         $lines = [
             ...$this->generatePhpDocBlock($phpDoc),
-            sprintf('protected static function %s(): %s', $name, $returnType),
+            sprintf('%s static function %s(): %s', $visibility, $name, $returnType),
             '{',
             sprintf('%sreturn %s;', self::TAB, $valueCode),
             '}'