Make klone more atomic

[inteon]

Don't remove full destination directory at start of sync, instead update the destination in place.

[ThatsMrTalbot]

If the goal is to make it more atomic, how does syncing in place do that? It just means if it fails make will be broken in more subtle ways with files missing / half written. If its breaks now its obvious because the directory is empty,

If we wanted to be atomic, we could leave the actual directories inside .klone directory and just replace symlinks. This would be entirely atomic. It would make it more of a pain to debug problems though as you would need to follow symlinks around.

[inteon]

The following issues should be solved with this PR:

• when running klone sync files are removed momentarily even when the destination is up-to-date
• when running klone sync the git diff explodes for a couple of seconds, causing vscode slow down

[ThatsMrTalbot]

Ah, so its less about atomic changes, its more about reducing churn during sync. If thats the goal then this PR would solve it

/lgtm

[inteon]

/approve

[cert-manager-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: inteon

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [inteon]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment