Proposal: allow users on try.gitea.io to create organizations

[wxiaoguang]

Now the users on try.gitea.io can not create organizations.

Many organization related bugs can not be test on try.gitea.io, eg:

• Can't add new WeChatWork webhook into Organization #17279
• Fix some org style problems #17807

[silverwind]

Might not affect all users, I can for example create orgs.

[techknowlogick]

It was disabled by default due to spammers using it rather than having to pass a captcha and email verification for each spam account they wished to create.

I can enable for your user if you wish.

[wxiaoguang]

Oh, if it is done by purpose, that's fine.