Add code to disable default scheduling policy (#1010)

## Description

All backups with corso are manual and use data sourced outside of kopia's control. Disable kopia's scheduling policy so we don't accidentally confuse it

## Type of change

<!--- Please check the type of change your PR introduces: --->
- [x] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 💻 CI/Deployment
- [ ] 🐹 Trivial/Minor

## Issue(s)

* closes #1009

## Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E

src/internal/kopia/conn.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"path/filepath"
 	"sync"
+	"time"
 
 	"github.com/kopia/kopia/repo"
 	"github.com/kopia/kopia/repo/blob"
@@ -21,6 +22,8 @@ const (
 	defaultKopiaConfigDir  = "/tmp/"
 	defaultKopiaConfigFile = "repository.config"
 	defaultCompressor      = "s2-default"
+	// Interval of 0 disables scheduling.
+	defaultSchedulingInterval = time.Second * 0
 )
 
 const defaultConfigErrTmpl = "setting default repo config values"
@@ -237,6 +240,10 @@ func (w *conn) setDefaultConfigValues(ctx context.Context) error {
 		changed = true
 	}
 
+	if updateSchedulingOnPolicy(defaultSchedulingInterval, p) {
+		changed = true
+	}
+
 	if !changed {
 		return nil
 	}
@@ -305,6 +312,19 @@ func updateRetentionOnPolicy(retention policy.RetentionPolicy, p *policy.Policy)
 	return true
 }
 
+func updateSchedulingOnPolicy(
+	interval time.Duration,
+	p *policy.Policy,
+) bool {
+	if p.SchedulingPolicy.Interval() == interval {
+		return false
+	}
+
+	p.SchedulingPolicy.SetInterval(interval)
+
+	return true
+}
+
 func (w *conn) getGlobalPolicyOrEmpty(ctx context.Context) (*policy.Policy, error) {
 	si := policy.GlobalPolicySourceInfo
 	return w.getPolicyOrEmpty(ctx, si)

src/internal/kopia/conn_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"math"
 	"testing"
+	"time"
 
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/kopia/snapshot/policy"
@@ -260,6 +261,18 @@ func (suite *WrapperIntegrationSuite) TestConfigDefaultsSetOnInitAndConnect() {
 				newRetention := policy.RetentionPolicy{KeepDaily: &newRetentionDaily}
 				updateRetentionOnPolicy(newRetention, p)
 
+				return nil
+			},
+		},
+		{
+			name: "Scheduling",
+			checkFunc: func(t *testing.T, p *policy.Policy) {
+				t.Helper()
+				require.Equal(t, time.Second*0, p.SchedulingPolicy.Interval())
+			},
+			mutator: func(innerCtx context.Context, p *policy.Policy) error {
+				updateSchedulingOnPolicy(time.Second*42, p)
+
 				return nil
 			},
 		},