[RIP-9] Added sample English documents of English transaction messages

[chenhaoxiang]

What is the purpose of the change

RocketMQ Developer Guide doc

Brief changelog

Organize the English translation of the RocketMQ transaction message sample into the doc/en directory

Verifying this change

Follow this checklist to help us incorporate your contribution quickly and easily. Notice, it would be helpful if you could finish the following 5 checklist(the last one is not necessary)before request the community to review your PR.

• Make sure there is a Github issue filed for the change (usually before you start working on it). Trivial changes like typos do not require a Github issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
• Format the pull request title like [ISSUE #123] Fix UnknownException when host config not exist. Each commit in the pull request should have a meaningful subject line and body.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit-test(over 80% coverage) to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add integration-test in test module.
• Run mvn -B clean apache-rat:check findbugs:findbugs checkstyle:checkstyle to make sure basic checks pass. Run mvn clean install -DskipITs to make sure unit-test pass. Run mvn clean test-compile failsafe:integration-test to make sure integration-test pass.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

[coveralls]

Coverage decreased (-0.03%) to 44.798% when pulling 5b47023 on chenhaoxiang:develop into 6a573a7 on apache:develop.

[wlliqipeng]

LGTM