Engine connection type via OAuth2

[NikitaShchienko]

Description

Support the new BPM Engine connection type via OIDC/OAuth2.

Motivation

Simplify connecting OpenBPM Control to Camunda + Keycloak.

[m-orlova]

QA notes

1. New authentication type "OAuth2" appears in BPM engine detail view.
   The following fields should be visible in BPM engine detail view if an authentication type = OAuth2:

   • Issuer URI: required, valid URL
   • Client Id: required
   • Client Secret: required
   • Scope (optional)

2. Lock of access token retrieval mechanism:

   • Enabled if application property flowset.control.engine.oauth2.lock-enabled is set as true (by default false)
   • If enabled:
     1. Control should not send requests for getting access token if a count of failed requests for getting access token exceeds value from flowset.control.engine.oauth2.max-retries (by default 5)
   2. In the Access token retrieval group in BPM engine detail view:
      • Checkbox "Locked" should set as true, button "Unlock" should be enabled
      • Lock date should be set
      • Retries should contain a count of made requests for getting an access token

3. Check cases when OIDC is used for Control and BPM engine:

   • The same settings for OIDC provider
   • The different settings for OIDC provider (e.g. different Keycloak instances)