Cleanup and add readme.md

README.md

README.txt

composer.json

package.json

section_library.info.yml

section_library.module

src/Controller/ChooseSectionFromLibraryController.php

src/Entity/SectionLibraryTemplateInterface.php

src/Entity/SectionLibraryTemplateViewsData.php

src/Form/AddSectionToLibraryForm.php

src/Form/AddTemplateToLibraryForm.php

src/Form/SectionLibraryForm.php