feat(snapshot): Expose config FetchTime for snapshots

[SimonRichardson]

Describe the purpose of your pull request

The following exposes the underlying config fetchTime so it's possible to
know when a given snapshot was taken. As snapshots act like readonly
encapsulations around configs, it's important to know if they're up to
date or not.

Related issues (only if applicable)

N/A

Requirement checklist (only if applicable)

• I have covered the applied changes with automated tests.
• I have executed the full automated test set against my changes.
• I have validated my changes against all supported platform versions.
• I have read and accepted the contribution agreement.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[codecov]

Codecov Report

Merging #55 (cc390f5) into master (ce5d7b9) will decrease coverage by 0.20%.
The diff coverage is 50.00%.

❗ Current head cc390f5 differs from pull request most recent head d50566a. Consider uploading reports for the commit d50566a to get more accurate results

@@            Coverage Diff             @@
##           master      #55      +/-   ##
==========================================
- Coverage   88.23%   88.03%   -0.21%     
==========================================
  Files           9        9              
  Lines        1258     1262       +4     
==========================================
+ Hits         1110     1111       +1     
- Misses        112      114       +2     
- Partials       36       37       +1     

Impacted Files	Coverage Δ
v7/snapshot.go	95.00% <50.00%> (-1.33%)	⬇️
v7/config_fetcher.go	86.93% <0.00%> (-0.51%)	⬇️

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[z4kn4fein]

Hi @SimonRichardson, thank you for the contribution!