Fix secrets SDK package to include the right files

[t1m0thyj]

What It Does
The publish workflow succeeded for the Secrets SDK, but resulted in an 80MB TGZ containing the wrong files:
https://zowe.jfrog.io/ui/repos/tree/General/npm-local-release/@zowe/secrets-for-zowe-sdk/-/@zowe/secrets-for-zowe-sdk-7.18.0-next.1.tgz

• Restore .npmignore from @traeok's repo to exclude Rust binaries in target dir
• Move JS source into lib folder and include it in the package
• Include Cargo.lock for keyring package in this repo
• Consolidate multiple .gitignore files into one

How to Test
Check out this branch
Run npm install and npm run build
Then cd into packages/secrets and run npm pack
Verify that the list of files added to the TGZ looks good

Review Checklist
I certify that I have:

• tested my changes
• added/updated automated tests
• updated the changelog
• followed the contribution guidelines

Additional Comments

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.02% ⚠️

Comparison is base (08be45b) 92.79% compared to head (b97a410) 92.78%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1769      +/-   ##
==========================================
- Coverage   92.79%   92.78%   -0.02%     
==========================================
  Files         422      423       +1     
  Lines        7165     7166       +1     
  Branches     1309     1309              
==========================================
  Hits         6649     6649              
- Misses        515      516       +1     
  Partials        1        1              

Files Changed	Coverage Δ
packages/secrets/src/index.ts	0.00% <0.00%> (ø)

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

[sonarcloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

0.0% Coverage
0.0% Duplication

Catch issues before they fail your Quality Gate with our IDE extension SonarLint

[zFernand0]

LGTM! 😋