Use rolling log for EQS storage

[sveitser]

• Update atomic store to 0.1.3.
• EQS: keep 5 latest log entries.
• Return Error instead of panicking when commiting faucet grant index.
• [x] Use seahorse 0.2.6 when available.
• https://github.com/EspressoSystems/seahorse/pull/219

Should we make the number of log entries the EQS keep configurable via env var?

Close #1183

[CLAassistant]

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