adjust state sync timeouts

[saketh-are]

This PR improves configurability of state sync by separating the config parameters for different kinds of timeouts:

• state_sync_timeout is used as it always has been when downloading from external storage.
• state_sync_p2p_timeout is used when downloading from peers in the network.
• state_sync_retry_timeout controls time between download attempts.

We also lower the number of retry attempts for p2p state sync from 5 to 3. Why? In testnet we see that requests are generally handled reliably and if a request fails it is usually because the target node is throttling incoming requests. In the case that peers are overwhelmed by traffic we would rather fall back to cloud storage sooner than send more requests (which will be throttled anyway).

[codecov]

Codecov Report

Attention: Patch coverage is 97.50000% with 1 line in your changes missing coverage. Please review.

Project coverage is 71.42%. Comparing base (c5de08f) to head (a671327).
Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
chain/client/src/sync/state/mod.rs	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #12425      +/-   ##
==========================================
+ Coverage   71.40%   71.42%   +0.01%     
==========================================
  Files         837      837              
  Lines      169023   169049      +26     
  Branches   169023   169049      +26     
==========================================
+ Hits       120699   120739      +40     
+ Misses      42980    42961      -19     
- Partials     5344     5349       +5     

Flag	Coverage Δ
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[VanBarbascu]

Other than that name refactoring this looks good.