refs #15589 [fid_adlr] transfer licenses from composer package into instance and embed DBIS package

* .gitignore changed: ignore copied dbis mixin in theme folder
* composer.json changed: add DBIS package AND add post-install / post-update - hooks to copy mixins after composer install or update
* config/application.config.php changed: also dbis module is still needed here for activation
* fid_adlr/config/vufind/config.ini changed: set adlr licenses configuration
* fid_adlr/config/vufind/fid.ini changed: set current api backend - remove on go live
* fid_adlr/config/vufind/permissionBehavior.ini added: derived from fid for correct handling of permissions in permissionHelper (defaultDeniedTemplateBehavior = true)
* fid_adlr/config/vufind/permissions.ini added: set permissions for licenses (currenty full_access only) and dbis (all)
* module/fid_adlr/config/module.config.php changed: add routes for licenses = dbis = databases
* module/fid_adlr/src/Controller/MyResearchController.php & MyResearchControllerFactory.php added: handle dbis and licenses actions
* themes/fid_adlr/languages/de.ini & themes/fid_adlr/languages/en.ini changed: add translations for dbis and licenses
* themes/fid_adlr/scss/_customMixins.scss & themes/fid_adlr/scss/compiled.scss changed: add styling for dbis, stub accordeon as mixin
* themes/fid_adlr/templates/footer.phtml added: for second link to dbis (databases) -> note #15652
* themes/fid_adlr/templates/myresearch/databases.phtml & dbis-content.phtml added: databases encapsulate dbis and licenses
* themes/fid_adlr/templates/myresearch/menu-additional-entries.phtml added: plugin menu entry to databases - called by fid/myresearch/menu
* themes/fid_adlr/theme.config.php changed: add finc-dbis theme