Add new option to customize inline model naming convention

[wing328]

• Add new option to customize inline model naming convention

e.g. --inline-schema-name-defaults arrayItemSuffix=_array_item (the default is _inner)

Only arrayItemSuffix, mapItemSuffix are supported at the moment.

cc @OpenAPITools/generator-core-team

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[wing328]

FYI --inline-schema-name-defaults to be renamed to --line-schema-options in v7.0.0 release: #16048