[Refactor]: optimized the Xline startup process

[themanforfree]

Please briefly answer these questions:

• what problem are you trying to solve? (or if there's no problem, what's the motivation for this change?) optimized the Xline startup process
• what changes does this pull request make? optimized the Xline startup process
• are there any non-obvious implications of these changes? (does it break compatibility with previous versions, etc) no

[codecov[bot]]

Codecov Report

Attention: 787 lines in your changes are missing coverage. Please review.

Comparison is base (fa656ad) 64.40% compared to head (89e7647) 75.32%. Report is 121 commits behind head on master.

Files	Patch %	Lines
curp/src/client/unary.rs	80.05%	44 Missing and 24 partials :warning:
curp/src/server/curp_node.rs	72.17%	53 Missing and 11 partials :warning:
xline/src/server/xline_server.rs	68.27%	46 Missing and 13 partials :warning:
xline/src/storage/alarm_store.rs	62.77%	44 Missing and 7 partials :warning:
curp/src/client/tests.rs	88.67%	23 Missing and 24 partials :warning:
utils/src/parser.rs	82.48%	32 Missing and 6 partials :warning:
xline/src/storage/kv_store.rs	5.12%	30 Missing and 7 partials :warning:
xline/src/server/maintenance.rs	51.35%	26 Missing and 10 partials :warning:
curp/src/rpc/connect.rs	70.00%	30 Missing and 3 partials :warning:
xline/src/server/command.rs	85.45%	20 Missing and 4 partials :warning:
... and 37 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #624 +/- ## =========================================== + Coverage 64.40% 75.32% +10.92% =========================================== Files 105 156 +51 Lines 18802 22921 +4119 Branches 18802 22921 +4119 =========================================== + Hits 12109 17265 +5156 + Misses 5955 4562 -1393 - Partials 738 1094 +356 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.