admin2: add extended ban features

[Dutchman101]

This request is the result of a discussion in #development on 12th June 2019.

Is your feature request related to a problem? Please describe.
admin2 currently has no feature parity with admin1 when it comes to ban features

Describe the solution you'd like
Make sure ban-related features that are present in admin1 will also be in admin2

Describe alternatives you've considered
The current ban-related features in admin2 aren't suitable for modern-day use. For example, there's only support for IP banning and not serial banning. Besides that, the set of features are very limited; see below at context. We really need a rewrite of ban features in admin2 overall, no alternatives.

Additional context

Current situation:

• There is only 1 way to add a ban: select player from list. You cannot offline-ban or add manual bans in the "Bans" tab.
• The ban you can add from playerlist is limited to an IP ban.
• The "Bans" tab offers an "Unban" button for IP bans. That's it.
• There is a ban search bar in the "Bans" tab

So we currently got a minimal, outdated set of ban-related features.

Required situation:

• You can add bans both from player list and the "Bans" tab.
• Both serial and IP bans are supported, online ban (from player list) and "Bans" tab should largely share the same ban customisation window

The ban customisation window should include:

For online bans:

• Ban reason
• Ban type (IP / serial)
• Duration (custom mins/days/hours and predefined values like in admin1)

For offline bans/from the "Bans" tab:

• "Ban IP" and "Ban serial" buttons like in admin1 (or as simplification over admin1, merge them into "Add ban" in admin2)
• Duration (custom mins/days/hours)
• Fields to enter player nick and ban reason

Implementing this list would result in feature parity with admin1 and suitability for modern-day usage in regards to banning.
To further explain, I will add screenshots of current ban-related features supported by admin1 that were described:

Issue description edit: added note about the ban search bar's presence in admin1. I personally don't think it's a hard requirement, but it would be nice to also offer it in admin2 to achieve full feature parity and not make admin2 less attractive than admin1 in terms of such a feature.

[Dutchman101]

Anything i wrote, especially the "required situation" is just a concept, input from others is welcomed.

In general, for all issues related to feature parity that could be created in the coming period: like we said in #development yesterday, adding additional features that go beyond just parity with admin1 can make usage of admin2 in a testing phase (running it for everyday administration on live servers) more attractive.

[FileEX]

My idea for offline ban:

Checkboxes for nick, ip and serial. When selected checkbox then editbox will be enabled. I think make it with one button like "Add ban" is better than different buttons for ip, serial and nick