[feature] path insert tot editor can be changed; [bugfix] some path saved in local machine

[dora-cmon]

Hello, Your work is really useful for me~ I add a feature and fix a bug, Thank you!

1. [feature] When I use hexo to write blog, I suppose the path inserting to article can be different, so I add config parameters "basePath", "prefix" and "suffix" to customize the path which shoud be inserted. I add explaination to README.
2. [bugfix] when path config use absolute path or use "${projectRoot}" variable, the image is always saved in local machine but not remote machine, I fixed it and judge remote connection or local use.