[JAVA-SPRING;KOTLIN-SPRING] improvement: Allow autoXSpringPaginated for endpoints without sort

[Picazsoo]

Change autoXSpringPaginated from a boolean switch into a string-enum option with three canonical values:

• none: disable auto-detection (default)
• page-size-sort: require page, size, and sort query parameters (identical to the previous true behavior)
• page-size: require only page and size; sort may be absent (new)

The legacy true/false values are still accepted as deprecated aliases for page-size-sort/none respectively. A deprecation warning is logged once via the generator logger only when the option is explicitly set to true/false; leaving the option unset keeps the silent none default with no warning.

• Add SpringPageableScanUtils.AutoPaginationMode enum and resolveAutoPaginationMode() to centralize parsing/validation/deprecation warnings shared by SpringCodegen and KotlinSpringServerCodegen.
• Update willBePageable, applyAutoXSpringPaginatedIfNeeded, and the scanSortValidationEnums/scanPageableDefaults/scanPageableConstraints/ scanAll methods to take AutoPaginationMode instead of boolean.
• Replace the boolean CLI switch with a documented string-enum CLI option in SpringCodegen and KotlinSpringServerCodegen (JavaCamelServerCodegen inherits the behavior since it extends SpringCodegen).
• Update existing tests to use the new enum where internal signatures changed; add new tests for page-size mode detection, deprecation warnings (once when explicit, never when unset), and invalid values.
• Regenerate docs/generators/{spring,kotlin-spring,java-camel}.md.

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Summary by cubic

Changes autoXSpringPaginated from a boolean switch into a string-enum option so Spring generators can auto-detect Pageable endpoints that have only page and size (no sort). Previously auto-detection required all three parameters; now page-size mode is available, and the default none disables auto-detection.

• Accepts canonical values none, page-size-sort, and page-size; page-size-sort matches the old true behavior.
• Legacy true/false values still work but log a deprecation warning when explicitly set; the unset default stays silent.
• Parsing and validation are centralized in SpringPageableScanUtils and shared by SpringCodegen, KotlinSpringServerCodegen, and JavaCamelServerCodegen.
• Adds tests for page-size detection, deprecation warnings, and invalid values; regenerates generator docs.

^{Written for commit 3c5e26a. Summary will update on new commits.}