New `kotools.types.NotBlankString` type

[LVMVRQUXL]

Description

Create a new NotBlankString type in the kotools.types package.

Keep it really simple by providing only its constructor.

Checklist

• [x] Create type with its builders.
• [x] Make the type serializable.
• [x] Make the type inheriting from Comparable.
• [x] Deprecate the kotools.types.string.NotBlankString type.
• [x] Refactor.
• [x] Update Work in progress section in changelog.

[LVMVRQUXL]

Done.