feat: separate cache from token.

[vkubiv]

Signed-off-by: Volodymyr Kubiv volodymyr.kubiv@euristiq.com

Title:
VC Wallet: decoupling KMS cache & token

Description:
Closes #2556

Summary:

Move token management from keyManager into a separate sessionManager.

[codecov]

Codecov Report

Merging #3249 (df3d768) into main (c826da9) will decrease coverage by 0.00%.
The diff coverage is 85.45%.

@@            Coverage Diff             @@
##             main    #3249      +/-   ##
==========================================
- Coverage   88.40%   88.39%   -0.01%     
==========================================
  Files         310      311       +1     
  Lines       42279    42310      +31     
==========================================
+ Hits        37375    37400      +25     
- Misses       3599     3603       +4     
- Partials     1305     1307       +2     

Impacted Files	Coverage Δ
pkg/wallet/session.go	81.15% <81.15%> (ø)
pkg/wallet/kmsclient.go	96.44% <84.21%> (+2.41%)	⬆️
pkg/wallet/contents.go	98.95% <100.00%> (ø)
pkg/wallet/storage.go	96.25% <100.00%> (+1.06%)	⬆️
pkg/wallet/wallet.go	98.32% <100.00%> (-0.01%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c826da9...df3d768. Read the comment docs.