Add Microsoft Teams integration (#6410)

* Add Microsoft Teams integration

* Fix method naming error

* Expand and clean up unit test coverage

* Update with PR feedback

* Add documentation, add In Progress logic/tests for Teams

* Fixed lowercase Slack

* Added docs; Updated PR suggestions;

* Fix broken tests

test/Core.Test/AdminConsole/Models/Data/Teams/TeamsBotCredentialProviderTests.cs

@@ -0,0 +1,56 @@
+using Bit.Core.AdminConsole.Models.Teams;
+using Microsoft.Bot.Connector.Authentication;
+using Xunit;
+
+namespace Bit.Core.Test.Models.Data.Teams;
+
+public class TeamsBotCredentialProviderTests
+{
+    private string _clientId = "client id";
+    private string _clientSecret = "client secret";
+
+    [Fact]
+    public async Task IsValidAppId_MustMatchClientId()
+    {
+        var sut = new TeamsBotCredentialProvider(_clientId, _clientSecret);
+
+        Assert.True(await sut.IsValidAppIdAsync(_clientId));
+        Assert.False(await sut.IsValidAppIdAsync("Different id"));
+    }
+
+    [Fact]
+    public async Task GetAppPasswordAsync_MatchingClientId_ReturnsClientSecret()
+    {
+        var sut = new TeamsBotCredentialProvider(_clientId, _clientSecret);
+        var password = await sut.GetAppPasswordAsync(_clientId);
+        Assert.Equal(_clientSecret, password);
+    }
+
+    [Fact]
+    public async Task GetAppPasswordAsync_NotMatchingClientId_ReturnsNull()
+    {
+        var sut = new TeamsBotCredentialProvider(_clientId, _clientSecret);
+        Assert.Null(await sut.GetAppPasswordAsync("Different id"));
+    }
+
+    [Fact]
+    public async Task IsAuthenticationDisabledAsync_ReturnsFalse()
+    {
+        var sut = new TeamsBotCredentialProvider(_clientId, _clientSecret);
+        Assert.False(await sut.IsAuthenticationDisabledAsync());
+    }
+
+    [Fact]
+    public async Task ValidateIssuerAsync_ExpectedIssuer_ReturnsTrue()
+    {
+        var sut = new TeamsBotCredentialProvider(_clientId, _clientSecret);
+        Assert.True(await sut.ValidateIssuerAsync(AuthenticationConstants.ToBotFromChannelTokenIssuer));
+    }
+
+    [Fact]
+    public async Task ValidateIssuerAsync_UnexpectedIssuer_ReturnsFalse()
+    {
+        var sut = new TeamsBotCredentialProvider(_clientId, _clientSecret);
+        Assert.False(await sut.ValidateIssuerAsync("unexpected issuer"));
+    }
+}