Add rate limiter for signing up

[JohnNiang]

What type of PR is this?

/kind feature
/area core
/milestone 2.7.x

What this PR does / why we need it:

Add rate limiter for signing up. We only allow 3 registrations within 1 hour by default, despite registration failure.

Special notes for your reviewer:

1. Start Halo and console.
2. Try to enable registration for public users.
3. Browse http://localhost:8090/console/login?type=signup
4. Input duplicate username for 4 times and see the result.
5. Or input valid username for 4 times and see the result.

Does this PR introduce a user-facing change?

限制注册接口的请求速率

[codecov]

Codecov Report

Merging #4128 (6710503) into main (cabcd98) will decrease coverage by 0.04%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##               main    #4128      +/-   ##
============================================
- Coverage     60.20%   60.17%   -0.04%     
  Complexity     2414     2414              
============================================
  Files           366      366              
  Lines         12575    12580       +5     
  Branches        906      906              
============================================
- Hits           7571     7570       -1     
- Misses         4564     4571       +7     
+ Partials        440      439       -1     

Impacted Files	Coverage Δ
...un/halo/app/theme/endpoint/PublicUserEndpoint.java	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

[guqing]

/lgtm

[f2c-ci-robot]

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