[GAE-Java] Remove String-specialized FFI classes and Simplify Java MessageManager interface

[zhanglei1949]

Fix issues #2194 #2189

[codecov-commenter]

Codecov Report

Merging #2195 (02ffa79) into main (5a4312d) will increase coverage by 27.06%.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2195       +/-   ##
===========================================
+ Coverage   40.03%   67.09%   +27.06%     
===========================================
  Files          87       89        +2     
  Lines        9752     9789       +37     
===========================================
+ Hits         3904     6568     +2664     
+ Misses       5848     3221     -2627     

Impacted Files	Coverage Δ
...aphscope/tests/kubernetes/test_resource_builder.py	0.00% <0.00%> (-100.00%)	⬇️
...on/graphscope/tests/kubernetes/test_demo_script.py	0.00% <0.00%> (-91.75%)	⬇️
python/graphscope/deploy/kubernetes/utils.py	11.90% <0.00%> (-58.58%)	⬇️
python/graphscope/deploy/kubernetes/cluster.py	23.01% <0.00%> (-51.70%)	⬇️
...thon/graphscope/tests/kubernetes/test_with_mars.py	0.00% <0.00%> (-44.83%)	⬇️
...n/graphscope/deploy/kubernetes/resource_builder.py	30.52% <0.00%> (-26.32%)	⬇️
python/graphscope/interactive/query.py	71.95% <0.00%> (-17.08%)	⬇️
python/graphscope/client/rpc.py	77.09% <0.00%> (ø)
python/graphscope/__init__.py	82.14% <0.00%> (ø)
python/graphscope/version.py	100.00% <0.00%> (ø)
... and 46 more

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