feat: Add app repo sync period

Created by: xuliwenwenwen

Signed-off-by: xuliwenwenwen liwenxu@yunify.com

What type of PR is this?

/kind feature

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes ##kubesphere/kubesphere#4107

Special notes for reviewers:

Does this PR introduced a user-facing change?

feat: Add app repo sync period

Additional documentation, usage docs, etc.: