Signed-off-by: marsishandsome marsishandsome@gmail.com

What problem does this PR solve?

Support configuration property file

What is changed and how it works?

add parameter tikv.config_file

• tikv java client config file
• default: null

This parameter can be passed by -Dtikv.config_file=/path/to/tikv_client_config.properties.

Here is an example of tikv_client_config.properties.

tikv.grpc.timeout_in_ms=150ms 
tikv.grpc.forward_timeout_in_ms=200ms
tikv.metrics.enable=true
tikv.metrics.port=3140

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation
• Need to be included in the release note