feat: add notification mail to admin for structure

src/configuration/config.ts

src/mailer/mail-templates/adminStructureCreate.ejs

src/mailer/mail-templates/structureDeletionNotification.ejs

src/mailer/mail-templates/structureDeletionNotification.json

...iler/mail-templates/structureModificationNotification.ejs

...ler/mail-templates/structureModificationNotification.json

src/structures/services/structures.service.ts

src/users/users.controller.ts

src/users/users.service.ts