optimize:FileConfiguration support system config file

[ldcsaa]

io.seata.config.FileConfiguration support system config file which with prefix 'file:'

#1577

[codecov-io]

Codecov Report

Merging #1598 into develop will increase coverage by 0.05%.
The diff coverage is n/a.

@@              Coverage Diff              @@
##             develop    #1598      +/-   ##
=============================================
+ Coverage      47.18%   47.24%   +0.05%     
+ Complexity      1778     1764      -14     
=============================================
  Files            362      359       -3     
  Lines          13225    12999     -226     
  Branches        1641     1617      -24     
=============================================
- Hits            6240     6141      -99     
+ Misses          6308     6193     -115     
+ Partials         677      665      -12

Impacted Files	Coverage Δ	Complexity Δ
...m/datasource/undo/parser/JacksonUndoLogParser.java	65.9% <0%> (-2.04%)	4% <0%> (ø)
...ta/rm/datasource/exec/AbstractDMLBaseExecutor.java	71.87% <0%> (-1.66%)	6% <0%> (-1%)
...seata/rm/datasource/sql/struct/TableMetaCache.java	55.69% <0%> (-0.28%)	14% <0%> (ø)
...rm/datasource/sql/struct/TableMetaCacheOracle.java	0% <0%> (ø)	0% <0%> (ø)	⬇️
...a/rm/datasource/undo/parser/KryoUndoLogParser.java
.../datasource/undo/parser/KryoSerializerFactory.java
...eata/rm/datasource/undo/parser/KryoSerializer.java
.../rm/datasource/undo/mysql/MySQLUndoLogManager.java	3.05% <0%> (+0.09%)	2% <0%> (ø)	⬇️
...m/datasource/undo/oracle/OracleUndoLogManager.java	3.14% <0%> (+0.09%)	2% <0%> (ø)	⬇️
...a/io/seata/core/store/db/LockStoreDataBaseDAO.java	53.01% <0%> (+0.1%)	20% <0%> (ø)	⬇️
... and 5 more

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[xingfudeshi]

LGTM.

[slievrly]

LGTM