Added obfuscator into databinding

[cristianciutea]

This PR will allow specifying in the integration configuration files, secrets obfuscated with newrelic cli

newrelic agent config obfuscate --key "encrypt_pass" --value='{"user":"test1","password":"test2"}'

e.g. of nginx configuration

integration_name: com.newrelic.nginx
variables:
  creds:
    obfuscated:
      key: encrypt_pass
      secret: result_from_newrelic_cli
instances:
  - name: nginx-server-metrics
    command: metrics
    arguments:
      status_url: http://${creds.user}:${creds.password}@example.com/status
      status_module: discover
      remote_monitoring: true
    labels:
      env: production
      role: load_balancer

[coveralls]

Pull Request Test Coverage Report for Build 391675528

• 31 of 56 (55.36%) changed or added relevant lines in 2 files are covered.
• 5 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.01%) to 58.222%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/databind/pkg/databind/config.go	2	10	20.0%
pkg/databind/internal/secrets/obfuscate.go	29	46	63.04%

Files with Coverage Reduction	New Missed Lines	%
pkg/databind/pkg/databind/config.go	1	60.24%
pkg/integrations/v4/logs/cfg_watcher.go	4	67.5%

Totals
Change from base Build 391305325:	-0.01%
Covered Lines:	11270
Relevant Lines:	19357

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 400798901

• 31 of 56 (55.36%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.008%) to 58.115%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/databind/pkg/databind/config.go	2	10	20.0%
pkg/databind/internal/secrets/obfuscate.go	29	46	63.04%

Files with Coverage Reduction	New Missed Lines	%
pkg/databind/pkg/databind/config.go	1	60.24%

Totals
Change from base Build 394042116:	-0.008%
Covered Lines:	11294
Relevant Lines:	19434

---

💛 - Coveralls

[carlosroman]

Nice, thanks for checking it still works with JSON 👍

[carlosroman]

If the text isn't JSON how about just returning the decrypted string instead instead of map with the key password? The KMS does something similar to this and so it makes the config nicer as if you know it is just one value you don't have to remember to do {something.password} and can use {something}.

[varas]

thanks for the comment!