Add ProgressBarAutomationPeer

[Takoooooo]

What does the pull request do?

Started to add automation peers for our controls,the main goal is to have all controls covered with the automation peers. ProgressBarAutomationPeer is a port of WPF version of it in general. I am planning to add integration tests for each control but i can't think of any useful integration tests for progress bars,if someone would have any good ideas i will implement the tests. Tested that ProgressBar plays well now with Windows and MacOS narrators.

Fixed issues

Part of #10143

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0029759-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0029765-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[robloo]

I thought we needed to add a header for code included from other projects?

[maxkatz6]

@robloo good question. I haven't paid attention as this code is as simple as it can be. And other automation classes (supposedly also from there) don't have any headers.

Upd: Seems like there is no issue as we have WPF in our NOTICE.md https://github.com/AvaloniaUI/Avalonia/blob/master/NOTICE.md#wpf