[FEAT] Allow to set headers on External Adaptor calls

[jpiabrantes]

Description I want to protect an external adaptor so that only whitelist nodes can access it.

Right now, I can protect whoever makes requests to my operator.

Requesters -> Operator -> External Adaptor (This is secured!)

However, I can't protect who calls my External Adaptor directly.

Malicious Actor -> External Adaptor (Not secured)

Ideally on the UI below, we would be able to set an auth header with a secret api key.

[QingyangKong]

Hi @jpiabrantes, thank you for the new feature suggestion and we will talk to the engineering team to see if this new feature can be added in following version.