Breaking Change: Variable definition

[richerfu]

Now we use OHOS_NDK_HOME to define the root directory for OHOS SDK. According to the normal naming method of Android, we should use OHOS_HOME instead of it and OHOS_SDK_NATIVE should be used for the sub-folder which named native.

But some crates and application use it as normal variable, so it's a breaking change.

• Upgrade some crates config or code. For example awc-ls-rs and cargo-zigbuild etc.
• Upgrade ohrs to use OHOS_HOME.
• Upgrade docs for it.

[github-actions]

@richerfu Please check this issue, thanks.