PLT-4403 Add server-based channel autocomplete, search and paging (#4585)

* Add more channel paging API

* Add channel paging support to client

* Add DB channel search functions

* Add API for searching more channels

* Add more channel search functionality to client

* Add API for autocompleting channels

* Add channel autocomplete functionality to the client

* Move to be deprecated APIs to their own file

* Final clean-up

* Fixes related to feedback

* Localization changes

* Add unit as suffix to timeout constants

webapp/tests/client_channel.test.jsx

@@ -271,6 +271,52 @@ describe('Client.Channels', function() {
         });
     });
 
+    it('getMoreChannelsPage', function(done) {
+        TestHelper.initBasic(() => {
+            TestHelper.basicClient().getMoreChannelsPage(
+                0,
+                100,
+                function(data) {
+                    assert.equal(data.length, 0);
+                    done();
+                },
+                function(err) {
+                    done(new Error(err.message));
+                }
+            );
+        });
+    });
+
+    it('searchMoreChannels', function(done) {
+        TestHelper.initBasic(() => {
+            TestHelper.basicClient().searchMoreChannels(
+                'blargh',
+                function(data) {
+                    assert.equal(data.length, 0);
+                    done();
+                },
+                function(err) {
+                    done(new Error(err.message));
+                }
+            );
+        });
+    });
+
+    it('autocompleteChannels', function(done) {
+        TestHelper.initBasic(() => {
+            TestHelper.basicClient().autocompleteChannels(
+                TestHelper.basicChannel().name,
+                function(data) {
+                    assert.equal(data != null, true);
+                    done();
+                },
+                function(err) {
+                    done(new Error(err.message));
+                }
+            );
+        });
+    });
+
     it('getChannelCounts', function(done) {
         TestHelper.initBasic(() => {
             TestHelper.basicClient().getChannelCounts(