feat: add funcs to generate and verify gpg signatures

[joey-bai]

To generate TSS cold wallets, we will need to generate signatures for
the commonKeychain and some way to validate those signatures.

Ticket: BG-45374

[codecov]

Codecov Report

Merging #2239 (20c8ed7) into master (b862eaf) will increase coverage by 52.61%.
The diff coverage is n/a.

❗ Current head 20c8ed7 differs from pull request most recent head e08c100. Consider uploading reports for the commit e08c100 to get more accurate results

@@             Coverage Diff             @@
##           master    #2239       +/-   ##
===========================================
+ Coverage        0   52.61%   +52.61%     
===========================================
  Files           0        6        +6     
  Lines           0      574      +574     
  Branches        0       94       +94     
===========================================
+ Hits            0      302      +302     
- Misses          0      262      +262     
- Partials        0       10       +10     

Flag	Coverage Δ
unit	52.61% <ø> (?)

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Impacted Files	Coverage Δ
modules/express/src/expressApp.ts	89.51% <0.00%> (ø)
modules/express/src/args.ts	100.00% <0.00%> (ø)
modules/express/src/retryPromise.ts	11.76% <0.00%> (ø)
modules/express/src/errors.ts	82.35% <0.00%> (ø)
modules/express/src/config.ts	94.73% <0.00%> (ø)
modules/express/src/clientRoutes.ts	32.48% <0.00%> (ø)