[dyncall] added dyncall module

[florianlenz]

Implemented the call module as described in #86

Verify

• check if all tasks from the issue are done
• test should pass

closes #86

[codecov-io]

Codecov Report

Merging #93 into develop will increase coverage by 0.02%.
The diff coverage is 89.18%.

@@             Coverage Diff             @@
##           develop      #93      +/-   ##
===========================================
+ Coverage    56.83%   56.85%   +0.02%     
===========================================
  Files           69       70       +1     
  Lines         4147     4184      +37     
===========================================
+ Hits          2357     2379      +22     
- Misses        1295     1308      +13     
- Partials       495      497       +2

Impacted Files	Coverage Δ
dyncall/dyncall_registry.go	89.18% <89.18%> (ø)
dapp/request_limitation/throttling.go	40% <0%> (-18%)	⬇️
backend/ws_transport.go	65.81% <0%> (-1.71%)	⬇️

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[borjantrajanoski]

We should probably check if map key exists first to avoid any potential panics

The current implementation might still work correctly in practice though, even without any changes

In the case of the key not existing in the modules map, nil will be sent to getCallMod.respChan so as long as it's properly handled, it shouldn't cause major issues

A proposed alternative that feels more safe in terms of potential panics

if mod, exists := modules[getCallMod.id]; exists {
    getCallMod.respChan <- mod
} else {
    getCallMod.respChan <- nil
}

Even though it might not make much of a difference in this use case, if CallModule was a struct with 2 fields, of type int and string, you wouldn't get a nil if the key is missing in the map with the unsafe usage, and you would get {0,"") as this would be corresponding to the default values of int and string type.

It's just that this time the default value of CallModule is nil because its an interface