Move assets into separate folder

frontend/src/assets/scss/bootstrapV5/_nav.scss

frontend/src/assets/scss/bootstrapV5/_navbar.scss

frontend/src/assets/scss/bootstrapV5/_pagination.scss

frontend/src/assets/scss/bootstrapV5/_popover.scss

frontend/src/assets/scss/bootstrapV5/_progress.scss

frontend/src/assets/scss/bootstrapV5/_reboot.scss

frontend/src/assets/scss/bootstrapV5/_root.scss

frontend/src/assets/scss/bootstrapV5/_spinners.scss

frontend/src/assets/scss/bootstrapV5/_tables.scss

frontend/src/assets/scss/bootstrapV5/_toasts.scss

frontend/src/assets/scss/bootstrapV5/_tooltip.scss

frontend/src/assets/scss/bootstrapV5/_transitions.scss

frontend/src/assets/scss/bootstrapV5/_type.scss

frontend/src/assets/scss/bootstrapV5/_utilities.scss

frontend/src/assets/scss/bootstrapV5/_variables.scss

frontend/src/assets/scss/bootstrapV5/bootstrap-grid.scss

frontend/src/assets/scss/bootstrapV5/bootstrap-reboot.scss

...tend/src/assets/scss/bootstrapV5/bootstrap-utilities.scss

frontend/src/assets/scss/bootstrapV5/bootstrap.scss

frontend/src/assets/scss/bootstrapV5/forms/_form-check.scss