Sync recent announced files with priority

[boqiu]

This PR solves multiple problems as following:

1. Upgrade rust toolchain to avoid macro-proc issue of latest rust analyzer in IDE.
2. Enhanced some sync relevant metrics.
3. Adjust the default config for file sync for better sync performance.
4. Supports to sync recent announced files with priority. This is helpful when node restarted and sync files from new connected peers.

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This change is 

[peilun-conflux]

Reviewed 13 of 13 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @0g-peterzhb)