Allow empty fields for firewall ports (#5809)

Closes #5809

See merge request ispconfig/ispconfig3!1247

Merge branch '5642-fail2ban-fails-to-detect-failed-dovecot-login-attempts-immediately' into 'develop'

move auth_verbose to pop3/imap protocol blocks

See merge request ispconfig/ispconfig3!1248

Merge branch '5642-fail2ban-fails-to-detect-failed-dovecot-login-attempts-immediately' into 'develop'

Resolve "Fail2ban fails to detect failed dovecot login attempts immediately"

Closes #5642

See merge request ispconfig/ispconfig3!1242

This reverts commit 67452af5.

Updated CP user passwords not saved in DB

Closes #5806

See merge request ispconfig/ispconfig3!1241

- don't use the quota-status check on unlisted recipients

Resolve "Dovecot dh.pem warning after ISPConfig install"

Closes #5802

See merge request ispconfig/ispconfig3!1239

Resolve "relayhost change not reflected"

Closes #5805

See merge request ispconfig/ispconfig3!1237

Merge branch '5550-centos-7-installer-clamd-service-restart-message-in-error-when-not-installing-amavisd' into 'develop'

Resolve "CentOS 7 installer clamd service restart message in error when not installing amavisd"

Closes #5550

See merge request ispconfig/ispconfig3!1222

Use DANE if TLSA records are present

Closes #5786

See merge request ispconfig/ispconfig3!1235

backups:  # backups and default exclusions

Closes #3270 and #5787

See merge request ispconfig/ispconfig3!1233

Don't jump to top of page when checkbox is clicked

Closes #5791

See merge request ispconfig/ispconfig3!1234

Resolve "Discussion: Problems with removed old TLS and CIPHERS"

Closes #5770

See merge request !1232

return both email and cc when forward_in_lda=n

See merge request ispconfig/ispconfig3!1229

remove unneeded "certificate exists" message

Closes #5757

See merge request ispconfig/ispconfig3!1206

fixed server id and type limit on interface (from !1230)

See merge request ispconfig/ispconfig3!1231

Resolve "Directive snippets not saved and not applied"

Closes #5785

See merge request ispconfig/ispconfig3!1230

- removed master_directive_snippet code that was (in 2016) accidently backported from master but never used