Modify blame options on the fly, or for a keybind

[ilan-schemoul]

Hey,
-m and -c (or -c -c) are crucial for git blame sometimes. But I can't add them on the setup() because if it's always enabled blame is incredibly slow on my large monorepo with large files.
Either:

• Add option to startup Blame with options (BlameToggle -m -c or require("blame").toggle(opts={"-m -c"})
• Better inside Blame view add shortcut to rerun blame with "-m" "-c" etc.

[jZhangTk]

I created the above PR to allow BlameToggle to accept options. Feedback is welcome.