Add Clear System Event Log support

[mattcburns]

Description

bmclib has clear system event log (SEL) support, add this to pbnj under the diagnostic service.

Why is this needed

Adding functionality supported by bmclib. This will help with cases like clear chassis intrusion alerts.

How Has This Been Tested?

Has been tested against several SuperMicro and Dell devices by checking SEL first, then clearing and checking the SEL was cleared.

How are existing users impacted? What migration steps/scripts do we need?

No impact, other than adding additional features.

Checklist:

I have:

• updated the documentation and/or roadmap (if required)
• added unit or e2e tests
• provided instructions on how to upgrade

[codecov]

Codecov Report

Merging #148 (2791f78) into main (c787762) will increase coverage by 0.54%.
The diff coverage is 92.30%.

❗ Current head 2791f78 differs from pull request most recent head 8ec8270. Consider uploading reports for the commit 8ec8270 to get more accurate results

@@            Coverage Diff             @@
##             main     #148      +/-   ##
==========================================
+ Coverage   81.33%   81.87%   +0.54%     
==========================================
  Files           9        9              
  Lines         466      491      +25     
==========================================
+ Hits          379      402      +23     
- Misses         74       75       +1     
- Partials       13       14       +1     

Files	Coverage Δ
grpc/server.go	88.88% <100.00%> (+0.36%)	⬆️
grpc/rpc/diagnostic.go	48.83% <91.30%> (+48.83%)	⬆️

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