feat: refactor TextAPI (cf. #50)

.gitignore

.gitlab-ci.yml

CHANGELOG.md

exist-app/build.properties

exist-app/modules/annotations.xqm

exist-app/modules/commons.xqm

exist-app/modules/tapi-collection.xqm

exist-app/modules/tapi-html.xqm

exist-app/modules/tapi-item.xqm

exist-app/modules/tapi-manifest.xqm

exist-app/modules/tapi-txt.xqm

exist-app/modules/tapi.xqm

exist-app/modules/testtrigger.xqm

exist-app/tests-runner.xq

exist-app/tests/commons-tests.xqm

exist-app/tests/tapi-collection-tests.xqm

exist-app/tests/tapi-html-tests.xqm

exist-app/tests/tapi-item-tests.xqm

exist-app/tests/tapi-manifest-tests.xqm

exist-app/tests/tapi-tests.xqm