feat: public key import and nicknames

[icoxxx]

Description:
This PR introduces a new feature: importing public keys and assigning them a nickname.
Key Additions:

• Local Database: Added a new entity to store public keys and their nicknames.
• CRUD Operations: Implemented functions to handle create, read, update, and delete operations.
• UI Integration: Added a section in Settings → Public Keys for managing imported keys.
• Allow the user to upload a zip or directory of public keys.
• UI Updates: Public keys are now displayed properly in TransactionDetails, Accounts, and ContactList pages and reusable components.

Backend Enhancements:

• Introduced a new endpoint in users.controller and a function to handle it in users.service. Allowing to check whether a public key owner exists within the organization without fetching and filtering all users.
• Unit Tests: Added test coverage for the new endpoint and service function.

PS: This is a fairly large feature, so I might have missed something - feel free to ping me if you spot anything :)

Related issue(s):
#1428 #1537

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.10%. Comparing base (0c1bfae) to head (815e329).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1573      +/-   ##
==========================================
+ Coverage   99.07%   99.10%   +0.02%     
==========================================
  Files         159      161       +2     
  Lines        5959     6148     +189     
  Branches     1101     1146      +45     
==========================================
+ Hits         5904     6093     +189     
  Misses         52       52              
  Partials        3        3              

Files with missing lines	Coverage Δ
back-end/apps/api/src/users/users.controller.ts	100.00% <100.00%> (ø)
back-end/apps/api/src/users/users.service.ts	100.00% <100.00%> (ø)
...nd/src/main/modules/ipcHandlers/localUser/index.ts	100.00% <100.00%> (ø)
...modules/ipcHandlers/localUser/publicKeyMappings.ts	100.00% <100.00%> (ø)
front-end/src/main/services/localUser/index.ts	100.00% <100.00%> (ø)
...nd/src/main/services/localUser/publicKeyMapping.ts	100.00% <100.00%> (ø)