(cherry picked from commit a54a784168c023d1f95c2c1ba0cd97659ffbd08c)

# Conflicts:
#	core/admin/Dockerfile
#	core/dovecot/Dockerfile
#	core/nginx/Dockerfile
#	core/none/Dockerfile
#	core/postfix/Dockerfile
#	optional/clamav/Dockerfile
#	optional/fetchmail/Dockerfile
#	optional/radicale/Dockerfile
#	optional/unbound/Dockerfile
#	setup/Dockerfile

- Moved run to bottom of Dockerfile to allow using unmodified / cached states.
- Simplified bash code in deploy.sh.
- Improved the large bash one-liner in CI.yml. It could not handle >9 for 1.x.

- fixed copy of qemu-arm-static for alpine
- added 'set -eu' safeguard
- silenced npm update notification
- added color to webpack call
- changed Admin-LTE default blue
  (core/admin/Dockerfile)

- AdminLTE 3 style tweaks
  (core/admin/assets/app.css)
  (core/admin/mailu/ui/templates/base.html)
  (core/admin/mailu/ui/templates/sidebar.html)

- localized datatables
  (core/admin/Dockerfile)
  (core/admin/assets/app.js)
  (core/admin/package.json)

- moved external javascript code to vendor.js
  (core/admin/assets/app.js)
  (core/admin/assets/vendor.js)
  (core/admin/webpack.config.js)

- added mailu logo
  (core/admin/assets/app.js)
  (core/admin/assets/app.css)
  (core/admin/assets/mailu.png)

- moved all inline javascript to app.js
  (core/admin/assets/app.js)
  (core/admin/mailu/ui/templates/domain/create.html)
  (core/admin/mailu/ui/templates/user/create.html)

- added iframe display of rspamd page
  (core/admin/assets/app.js)
  (core/admin/mailu/ui/views/base.py)
  (core/admin/mailu/ui/templates/sidebar.html)
  (core/admin/mailu/ui/templates/antispam.html)

- updated language-selector to display full language names and use post
  (core/admin/assets/app.js)
  (core/admin/mailu/__init__.py)
  (core/admin/mailu/utils.py)
  (core/admin/mailu/ui/views/languages.py)

- added fieldset to group and en/disable input fields
  (core/admin/assets/app.js)
  (core/admin/mailu/ui/templates/macros.html)
  (core/admin/mailu/ui/templates/user/settings.html)
  (core/admin/mailu/ui/templates/user/reply.html)

- added clipboard copy buttons
  (core/admin/assets/app.js)
  (core/admin/assets/vendor.js)
  (core/admin/mailu/ui/templates/macros.html)
  (core/admin/mailu/ui/templates/domain/details.html)

- cleaned external javascript imports
  (core/admin/assets/vendor.js)

- pre-split first hostname for further use
  (core/admin/mailu/__init__.py)
  (core/admin/mailu/models.py)
  (core/admin/mailu/ui/templates/client.html)
  (core/admin/mailu/ui/templates/domain/signup.html)

- cache dns_* properties of domain object (immutable during runtime)
  (core/admin/mailu/models.py)
  (core/admin/mailu/ui/templates/domain/details.html)

- fixed and splitted dns_dkim property of domain object (space missing)
- added autoconfig and tlsa properties to domain object
  (core/admin/mailu/models.py)

- suppressed extra vertical spacing in jinja2 templates
- improved accessibility for screen reader
  (core/admin/mailu/ui/templates/**.html)

- deleted unused/broken /user/forward route
  (core/admin/mailu/ui/templates/user/forward.html)
  (core/admin/mailu/ui/views/users.py)

- updated gunicorn to 20.1.0 to get rid of buffering error at startup
  (core/admin/requirements-prod.txt)

- switched webpack to production mode
  (core/admin/webpack.config.js)

- added css and javascript minimization
- added pre-compression of assets (gzip)
  (core/admin/webpack.config.js)
  (core/admin/package.json)

- removed obsolte dependencies
- switched from node-sass to dart-sass
  (core/admin/package.json)

- changed startup cleaning message from error to info
  (core/admin/mailu/utils.py)

- move client config to "my account" section when logged in
  (core/admin/mailu/ui/templates/sidebar.html)

This reverts commit f8362d04.

It turns out we were all blind and admin *does* use MailuStart

This reverts commit c787e4bd.

This fix https://github.com/Mailu/Mailu/issues/918

Bash shell is used by default in Kubernetes' dashboard console, which is very
useful for admins.