GC SharePoint Collection Framework (#1444)

## Description
Boilerplate for SharePoint collection 

## Type of change

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

src/internal/connector/sharepoint/collection.go

@@ -0,0 +1,54 @@
+package sharepoint
+
+import (
+	"io"
+
+	"github.com/alcionai/corso/src/internal/connector/graph"
+	"github.com/alcionai/corso/src/internal/connector/support"
+	"github.com/alcionai/corso/src/internal/data"
+	"github.com/alcionai/corso/src/pkg/path"
+)
+
+type DataCategory int
+
+//go:generate stringer -type=DataCategory
+const (
+	Unknown DataCategory = iota
+	List
+	Drive
+)
+
+var (
+	_ data.Collection = &Collection{}
+	_ data.Stream     = &Item{}
+)
+
+type Collection struct {
+	data chan data.Stream
+	// folderPath indicates the hierarchy within the collection
+	folderPath path.Path
+	// M365 IDs of the items of this collection
+	service       graph.Service
+	statusUpdater support.StatusUpdater
+}
+
+func (sc *Collection) FullPath() path.Path {
+	return sc.FullPath()
+}
+
+func (sc *Collection) Items() <-chan data.Stream {
+	return sc.data
+}
+
+type Item struct {
+	id   string
+	data io.ReadCloser
+}
+
+func (sd *Item) UUID() string {
+	return sd.id
+}
+
+func (sd *Item) ToReader() io.ReadCloser {
+	return sd.data
+}

src/internal/connector/sharepoint/datacategory_string.go

@@ -0,0 +1,25 @@
+// Code generated by "stringer -type=DataCategory"; DO NOT EDIT.
+
+package sharepoint
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[Unknown-0]
+	_ = x[List-1]
+	_ = x[Drive-2]
+}
+
+const _DataCategory_name = "UnknownListDrive"
+
+var _DataCategory_index = [...]uint8{0, 7, 11, 16}
+
+func (i DataCategory) String() string {
+	if i < 0 || i >= DataCategory(len(_DataCategory_index)-1) {
+		return "DataCategory(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _DataCategory_name[_DataCategory_index[i]:_DataCategory_index[i+1]]
+}