Allow all Context implicit params to be overrideable in extra

[MKRhere]

Instead of switching between ctx and ctx.telegram/bot.telegram methods, it may be beneficial and fluent to only use Context methods. In v5, all Context methods must allow their implicit params to be overridden by extra.

Example:

// use current chat
await ctx.sendMessage("Hello!");

// send message to another chat
await ctx.sendMessage("Hello!", { chat_id: -100xxxxxxxxx });

This feels more intuitive. This is a tracking issue for v5.

This proposal does not remove or endanger {bot|ctx}.telegram, it's purely additive.