Remove unused parts from previous theme

.github/workflows/main.yml

.gitignore

exampleSite/assets/_custom.scss

exampleSite/assets/_variables.scss

exampleSite/content.bn/_index.md

exampleSite/content.en/_index.md

exampleSite/content.en/docs/example/_index.md

.../content.en/docs/example/collapsed/3rd-level/4th-level.md

...ite/content.en/docs/example/collapsed/3rd-level/_index.md

exampleSite/content.en/docs/example/collapsed/_index.md

exampleSite/content.en/docs/example/hidden.md

...eSite/content.en/docs/example/table-of-contents/_index.md

...ite/content.en/docs/example/table-of-contents/with-toc.md

.../content.en/docs/example/table-of-contents/without-toc.md

exampleSite/content.en/docs/shortcodes/_index.md

exampleSite/content.en/docs/shortcodes/buttons.md

exampleSite/content.en/docs/shortcodes/columns.md

exampleSite/content.en/docs/shortcodes/details.md

exampleSite/content.en/docs/shortcodes/expand.md

exampleSite/content.en/docs/shortcodes/hints.md