ERC-1129 Standardised DAPP announcements

Stagnant

⚙️ Functions this standard introduces (5)

`0xcde4ef4d`	`givePostingPermission(address,bool,string)`
`0x5058c5bb`	`postAnnouncement(string)`
`0x7558cc30`	`readPosts(uint256)`
`0x4138aef6`	`removeAnnouncement(uint256,string)`
`0xf426bb48`	`theNumberOfAnnouncements()`