Allow users to not display all tags on revision graph

Some projects have so many tags that revision graph in TortoiseGit becomes almost unusable. I suggest adding an option to hide them.

What steps will reproduce the problem?

1. Open revision graph of a repository with many tags

What is the expected output? What do you see instead?

I expect being able to see the recent branches. What I actually see is lots of tags and viewing the branches is difficult.

What version of TortoiseGit and Git are you using? On what operating system?

TortoiseGit 2.8.0.0, git 2.21, Windows 8.1 x64

Please provide any additional information below.

I actually did this locally and am willing to send a PR if this feature request is approved.