Implement server announcement

[Akka0]

Description

Allow server admin to send the in-game announcement by command or auto announce by cron task.

Command Usage

This command can be used in both console or game chat
a <tpl templateId|refresh|revoke templateId|content>

Example

/a tpl 1 // send the template 1 announcement instantly
/a refresh // refresh Announcement.json config file (You can put it in ./data/Announcement.json outside the jar)
/a revoke 1 // revoke the template 1 announcement config
/a xxxxxx // send an announcement instantly

Config File

Announcement.json

[
{
    "templateId" : 2,
    "type" : "COUNTDOWN", // CENTER or COUNTDOWN
    "frequency" : 1,
    "content": "Welcome to grasscutter PS!",
    "beginTime": "2022-06-01T00:00:00+08:00",
    "endTime": "2022-06-01T00:08:00+08:00",
    "tick" : false, // if set to true, it will auto send by cron task, or you need to send it by /a tpl <id>
    "interval": 1 // interval of time (minutes)
  }
]

Preview

Issues fixed by this PR

Type of changes

• Bug fix
• New feature
• Enhancement
• Documentation

Checklist:

• My code follows the style guidelines of this project
• My pull request is unique and no other pull requests have been opened for these changes
• I have read the Contributing note and Code of conduct
• I am responsible for any copyright issues with my code if it occurs in the future.