plugin: preload git plugin by default

[magik6k]

Suggested by @lgierth an IRC, enabling the git plugin is rather painful experience for anyone wanting to do anything git related:

• Linux users have to setup Go workspace, compile the plugin and then put in a right directory
• All the others (osx/windows/*) have to setup Go workspace, unncomment ipldgit line in preload file and compile/install go-ipfs (bonus pain points when using something like ipfs-desktop)

Adding the plugin to preload_list adds about 100K to the binary size, and given that it is 43M it's rather negligible.

[Kubuxu]

The plugin would have to be imported through gx for it to work.

Can you figure out why CI failed?

[ghost]

Adding the plugin to preload_list adds about 100K to the binary size, and given that it is 43M it's rather negligible.

Being able to do Git things is absolutely worth the 100KB :)

[whyrusleeping]

The sha1 object thing by default bothers me slightly. Maybe we should just put efforts into getting the plugins up on dists?

[ghost]

Maybe let's couple allowing sha1 to git CIDs only then. We'll have the same issue with js-ipfs and ipfs-companion.

[whyrusleeping]

Alright, fine. You guys win this battle