refactor: rename limiter api

[baojinri]

Which issue does this PR close?

Closes #

Rationale for this change

Friendly user

What changes are included in this PR?

• Rename TokenBucketFillRate to Limit.
• Rename TokenBucketBurstEventCapacity to Burst.

Are there any user-facing changes?

none

How does this change test

CI

[codecov]

Codecov Report

Merging #192 (df33569) into main (7f1354e) will increase coverage by 20.98%.
The diff coverage is 59.49%.

@@             Coverage Diff             @@
##             main     #192       +/-   ##
===========================================
+ Coverage   39.66%   60.65%   +20.98%     
===========================================
  Files          34       41        +7     
  Lines        4213     4892      +679     
===========================================
+ Hits         1671     2967     +1296     
+ Misses       2317     1545      -772     
- Partials      225      380      +155     

Impacted Files	Coverage Δ
pkg/coderr/code.go	0.00% <ø> (ø)
server/cluster/metadata/types.go	0.00% <0.00%> (ø)
server/coordinator/procedure/util.go	0.00% <ø> (ø)
server/storage/meta.go	0.00% <ø> (ø)
server/storage/storage_impl.go	57.21% <0.00%> (-5.10%)	⬇️
server/member/watch_leader.go	40.62% <20.00%> (-2.71%)	⬇️
server/cluster/manager.go	41.88% <34.88%> (ø)
server/member/member.go	47.39% <45.00%> (-1.32%)	⬇️
server/coordinator/scheduler/scheduler_manager.go	53.96% <47.36%> (ø)
server/coordinator/procedure/manager_impl.go	73.68% <55.55%> (+73.68%)	⬆️
... and 13 more

... and 3 files with indirect coverage changes

[chunshao90]

LGTM

[chunshao90]

LGTM