Add expression support to endpoint definition attributes for handling endpoints in the HTTP connector.

[chathuranga-jayanath-99]

Purpose

The HTTP connector uses the following format for maintaining endpoint definitions. To support this format, expression support for endpoint definition attributes is required. This PR introduces the necessary changes to enable this support for the use of HTTP connector. Note that expression support for timeout-duration is already available.

<http method="get" uri-template="{uri.var.base}{+uri.var.path}{+uri.var.query}">
  <timeout>
      <duration>{get-property('timeoutDuration')}</duration>
      <responseAction>{get-property('timeoutAction')}</responseAction>
  </timeout>
  <suspendOnFailure>
      <errorCodes>{get-property('suspendErrorCodes')}</errorCodes>
      <initialDuration>{get-property('suspendInitialDuration')}</initialDuration>
      <maximumDuration>{get-property('suspendMaximumDuration')}</maximumDuration>
      <progressionFactor>{get-property('suspendProgressionFactor')}</progressionFactor>
  </suspendOnFailure>
  <markForSuspension>
      <errorCodes>{get-property('retryErrorCodes')}</errorCodes>
      <retriesBeforeSuspension>{get-property('retryCount')}</retriesBeforeSuspension>
      <retryDelay>{get-property('retryDelay')}</retryDelay>
  </markForSuspension>
</http>

[GDLMadushanka]

Please squash these commits to a single one

[arunans23]

Shall we explore whether we can resolve the values at the first request and use them for consecutive requests? Also lets try to do it for HTTP Endpoint only so that we do not have to modify the behaviour of other endpoint types.