Investigate other proxy mechanisms

[mostafa]

With the removal of the elastic proxy mechanism in #359, there is currently a single proxy type that connects incoming connections to a limited set of connections (in the available connections pool). The idea here is to investigate other proxy mechanisms, for example, one is being developed in #398 (#512) to enable multiple proxies to be connected to a single server instances to allow routing between multiple database servers. This enable advanced proxying (#337) and routing (#399). These are the objectives:

• [ ] 1. List different proxy mechanisms in similar products (see #206)
• [ ] 2. Analyzing them to find appropriate proxy mechanisms for GatewayD
• [ ] 3. Write a report based on the analysis
• [ ] 4. Create tickets (epics and others) for the chosen mechanisms