feat(newrelic): APM application id can be looked up by name

[3bbbeau]

Summary

This is intended to be a quality of life feature to allow ArgoCD ApplicationSet resources to minimize boilerplate when dealing with NewRelic APM resources across multiple environments.

Currently

• An application programmatically uses the NR SDK to report to NewRelic
• NewRelic APM Application ID has to then be retrieved following the first run of an application from the NR Dashboard and added to an ArgoCD Application via the annotation, across multiple environments.

---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  annotations:
    notifications.argoproj.io/subscribe.<trigger-name>.newrelic: 123456789

Desired

Using ArgoCD ApplicationSet resources, the annotation can be either provided via the application id as the above example, or instead by name, e.g. MyApp-{{ .values.env }}:

---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  annotations:
    notifications.argoproj.io/subscribe.<trigger-name>.newrelic: MyApp-Dev

---

Logic

If dest.Recipient can be parsed to an int, then the application id was directly provided and logic remains as before.

If dest.Recipient cannot be parsed to an integer, then it was passed by name (since all NewRelic APM IDs are defined as integers within the schema) and we call /v2/applications.json to query using filter[name]

If /v2/applications.json returns multiple application IDs then an error is returned, as we can't determine which application id to use to place the deployment marker.

[pasha-codefresh]

Hey @3bbbeau could you please address comments?

[codecov]

Codecov Report

❌ Patch coverage is 65.90909% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.12%. Comparing base (da04400) to head (1582b2f).
⚠️ Report is 27 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/services/newrelic.go	65.90%	9 Missing and 6 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #361      +/-   ##
==========================================
+ Coverage   55.41%   60.12%   +4.71%     
==========================================
  Files          46       48       +2     
  Lines        4125     3742     -383     
==========================================
- Hits         2286     2250      -36     
+ Misses       1511     1131     -380     
- Partials      328      361      +33     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[3bbbeau]

@pasha-codefresh Hey, I've addressed all but #361 (comment) which I'm not sure I understand broader implementation details