feature:support protobuf maven plugin

[github-ygy]

Ⅰ. Describe what this PR did

support protobuf maven plugin

Ⅱ. Does this pull request fix one issue?

support protobuf maven plugin to generate java code

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #1489 into develop will increase coverage by 11.65%.
The diff coverage is n/a.

@@              Coverage Diff               @@
##             develop    #1489       +/-   ##
==============================================
+ Coverage       35.1%   46.75%   +11.65%     
+ Complexity      2281     1730      -551     
==============================================
  Files            443      353       -90     
  Lines          23838    12941    -10897     
  Branches        3316     1618     -1698     
==============================================
- Hits            8369     6051     -2318     
+ Misses         14352     6238     -8114     
+ Partials        1117      652      -465

Impacted Files	Coverage Δ	Complexity Δ
...eata/rm/datasource/exec/LockConflictException.java	0% <0%> (-100%)	0% <0%> (-2%)
.../seata/rm/datasource/exec/LockRetryController.java	0% <0%> (-92.31%)	0% <0%> (-4%)
...ta/rm/datasource/exec/AbstractDMLBaseExecutor.java	9.37% <0%> (-62.5%)	2% <0%> (-4%)
...java/io/seata/rm/datasource/ConnectionContext.java	13.33% <0%> (-33.34%)	3% <0%> (-8%)
...a/rm/datasource/exec/LockWaitTimeoutException.java	0% <0%> (-33.34%)	0% <0%> (-1%)
...n/java/io/seata/rm/datasource/ConnectionProxy.java	8.51% <0%> (-14.38%)	4% <0%> (-6%)
...java/io/seata/rm/datasource/DataSourceManager.java	25.75% <0%> (-1.67%)	7% <0%> (ø)
...o/seata/rm/datasource/AbstractConnectionProxy.java	11.9% <0%> (-1.2%)	5% <0%> (-1%)
.../rm/datasource/exec/BaseTransactionalExecutor.java	17.39% <0%> (-0.87%)	6% <0%> (-1%)
.../main/java/io/seata/rm/datasource/AsyncWorker.java	15.58% <0%> (-0.86%)	4% <0%> (ø)
... and 19 more

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[slievrly]

@github-ygy Why do you need to move the location of the proto file?

[xingfudeshi]

LGTM.

[leizhiyuan]

LGTM

[ujjboy]

LGTM