Add keepalive_time setting for MySQL connections

[Keviro]

Is your feature request related to a problem? Please describe.
I am currently experiencing a problem using two different hosts. One of them uses cosmicguard and requires the server to send a keepalive to keep outgoing database connections alive. Otherwise if they are idle for too long cosmic will forget the connection. Sadly I noticed that eco does not feature that setting yet.

Describe the solution you'd like
Add the keepalive_time config option

[SenPr]

+1, seems simple enough but very useful feature

[ammodev]

Are there any updates on this? I currently experience the same issue and its already been a month with no response?