investigate alternative to relay pings/why we need them

[danisharora099]

Problem

#1189 (comment) made us aware that relay pings (sending messages over the relay protocol manually) are required to ensure connection stays alive.
This isn't ideal as we end up sending a lot of messages (maybe spam).

Proposed Solutions

This issue should track:

• why we need relay pings
• alternative to relay pings if possible
• if we can reopen the connection after it closes (in 10 mins)
• confirm if after 10 mins, does message sending and receiving both fail, or just receiving?

Notes

Refer to some investigation been done in #1189

[fryorcraken]

The output of this issue should be:

• relay ping are removed
• Yet, a browser is able to use Relay for an extensive period of time (e.g. 1 hour)

[fryorcraken]

At this point in time it does not really make sense to use Relay anyways because we can only connect to nodes via wss.
This issue can be addressed once Relay over WebRTC is done and we start to worry about connection management for it.

Let's keep the ping for now as some projects do use Relay. Do note that in terms of documentation, we will only push light client protocols.