[Multi-Database Support] Remove unused datasource configs

[shoothzj]

What's the purpose of this PR

Remove unnecessary set names utf8mb4.
We have set names utf8mb4 configed in apollo-common's application.yaml spring.jpa.datasource.hikari.connectionInitSql.
I preferred to keep application.yaml, it's more flexible.
Tested with wireshark

[codecov]

Codecov Report

Merging #4754 (a5d4fbe) into master (645b215) will increase coverage by 0.04%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #4754      +/-   ##
============================================
+ Coverage     47.22%   47.27%   +0.04%     
+ Complexity     1657     1655       -2     
============================================
  Files           349      346       -3     
  Lines         10691    10662      -29     
  Branches       1062     1058       -4     
============================================
- Hits           5049     5040       -9     
+ Misses         5336     5316      -20     
  Partials        306      306              

Impacted Files	Coverage Δ
...oServiceRegistryDeregisterApplicationListener.java	30.00% <0.00%> (-45.00%)	⬇️

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[nobodyiam]

I believe we could remove this file as well as the datasource folder, application-ctrip.properties and application-ctrip.yml, they are for Ctrip internal use only.

[shoothzj]

@nobodyiam Fixed. Thanks for your sharing.

[nobodyiam]

LGTM