create --env-file for pouch run & pouch create

[lang710]

Ⅰ. Describe what this PR did

create --env-file for pouch run & pouch create

Ⅱ. Does this pull request fix one issue?

try to fix #2857

Ⅲ. Why don't you add test cases (unit test/integration test)? (你真的觉得不需要加测试吗？)

add unit test and simple integration test

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[pouchrobot]

Thanks for your contribution. 🍻 @lang710
While we thought PR TITLE could be more specific, longer than 20 chars.
Please edit this PR title instead of opening a new one.
More details, please refer to https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md

[codecov]

Codecov Report

❗ No coverage uploaded for pull request head (master@0c23a4d). Click here to learn what that means.
The diff coverage is n/a.

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[pouchrobot]

We found this is your first time to contribute to pouch, @lang710
👏 We really appreciate it.
Just remind that you have read the contribution guide: https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md
If you didn't, you should do that first. If done, welcome again and please enjoy hacking! 🍻

[CodeJuan]

Hi @lang710
I was wondering if you could rebase & squash commits and signoff?

[pouchrobot]

@lang710 Thanks for your contribution. 🍻
Please sign off in each of your commits.

[pouchrobot]

ping @lang710
Conflict happens after merging a previous commit.
Please rebase the branch against master and push it back again. Thanks a lot.