Add a helper function that returns site ID and site URL in a Site struct (#2778)

This PR adds a helper function that returns a newly introduced `Site` struct that has a site ID and site webURL for a given m365 tenant.

---

#### Does this PR need a docs update or release note?
- [X] ⛔ No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [X] 🌻 Feature

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #2777 

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [X] ⚡ Unit test

```
--- PASS: TestM365IntegrationSuite (2.49s)
    --- PASS: TestM365IntegrationSuite/TestSites (1.82s)
        --- PASS: TestM365IntegrationSuite/TestSites/site (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#01 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#02 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#03 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#04 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#05 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#06 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#07 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#08 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#09 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#10 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#11 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#12 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#13 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#14 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#15 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#16 (0.00s)
        --- PASS: TestM365IntegrationSuite/TestSites/site#17 (0.00s)
```

src/pkg/services/m365/m365.go

@@ -86,6 +86,34 @@ func UserPNs(ctx context.Context, acct account.Account, errs *fault.Bus) ([]stri
 	return ret, nil
 }
 
+type Site struct {
+	// WebURL that displays the item in the browser
+	WebURL string
+
+	// ID is of the format: <site collection hostname>.<site collection unique id>.<site unique id>
+	// for example: contoso.sharepoint.com,abcdeab3-0ccc-4ce1-80ae-b32912c9468d,xyzud296-9f7c-44e1-af81-3c06d0d43007
+	ID string
+}
+
+// Sites returns a list of Sites in a specified M365 tenant
+func Sites(ctx context.Context, acct account.Account, errs *fault.Bus) ([]*Site, error) {
+	gc, err := connector.NewGraphConnector(ctx, graph.HTTPClient(graph.NoTimeout()), acct, connector.Sites, errs)
+	if err != nil {
+		return nil, errors.Wrap(err, "initializing M365 graph connection")
+	}
+
+	// gc.Sites is a map with keys: SiteURL, values: ID
+	ret := make([]*Site, 0, len(gc.Sites))
+	for k, v := range gc.Sites {
+		ret = append(ret, &Site{
+			WebURL: k,
+			ID:     v,
+		})
+	}
+
+	return ret, nil
+}
+
 // SiteURLs returns a list of SharePoint site WebURLs in the specified M365 tenant
 func SiteURLs(ctx context.Context, acct account.Account, errs *fault.Bus) ([]string, error) {
 	gc, err := connector.NewGraphConnector(ctx, graph.HTTPClient(graph.NoTimeout()), acct, connector.Sites, errs)
@@ -96,7 +124,7 @@ func SiteURLs(ctx context.Context, acct account.Account, errs *fault.Bus) ([]str
 	return gc.GetSiteWebURLs(), nil
 }
 
-// SiteURLs returns a list of SharePoint sites IDs in the specified M365 tenant
+// SiteIDs returns a list of SharePoint sites IDs in the specified M365 tenant
 func SiteIDs(ctx context.Context, acct account.Account, errs *fault.Bus) ([]string, error) {
 	gc, err := connector.NewGraphConnector(ctx, graph.HTTPClient(graph.NoTimeout()), acct, connector.Sites, errs)
 	if err != nil {

src/pkg/services/m365/m365_test.go

@@ -4,7 +4,6 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 
 	"github.com/alcionai/corso/src/internal/tester"
@@ -34,9 +33,8 @@ func (suite *M365IntegrationSuite) TestUsers() {
 	)
 
 	users, err := Users(ctx, acct, fault.New(true))
-	require.NoError(t, err)
-	require.NotNil(t, users)
-	require.Greater(t, len(users), 0)
+	assert.NoError(t, err)
+	assert.NotEmpty(t, users)
 
 	for _, u := range users {
 		suite.Run("user_"+u.ID, func() {
@@ -48,3 +46,25 @@ func (suite *M365IntegrationSuite) TestUsers() {
 		})
 	}
 }
+
+func (suite *M365IntegrationSuite) TestSites() {
+	ctx, flush := tester.NewContext()
+	defer flush()
+
+	var (
+		t    = suite.T()
+		acct = tester.NewM365Account(suite.T())
+	)
+
+	sites, err := Sites(ctx, acct, fault.New(true))
+	assert.NoError(t, err)
+	assert.NotEmpty(t, sites)
+
+	for _, s := range sites {
+		suite.Run("site", func() {
+			t := suite.T()
+			assert.NotEmpty(t, s.WebURL)
+			assert.NotEmpty(t, s.ID)
+		})
+	}
+}