Add troubleshooting steps for local setup issues (solves/32193)

[sundaram2021]

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[sundaram2021]

I have added troubleshooting guide for the issue we get while setting up the gitea repo locally after forking

problem looks like this

solution
1.

2.

And It solves the problem

[lunny]

Please send the pull request to docs repository. https://gitea.com/gitea/docs

[sundaram2021]

will do it but it will take some time for registration
thanks

[wxiaoguang]

These information are too general and not related to Gitea, so I do not think it is suitable to put into Gitea's repo.

For example: you could see curl error: RPC failed or HTTP/2 stream was not closed cleanly, and you could also see "can't resolve host" and "connection reset", it's impossible to tech developers to "fix" their computer.

git clone --depth 1 is a general git command and it is not generally useful. Many users would like to have the full clone. It's not suitable to mention --depth 1 in every git project's document (no project does so!)

[wxiaoguang]

Thank you for your PR, the document is maintained in https://gitea.com/gitea/docs