More description formatting and 2 new options

[rhullah]

Perform additional formatting w/ options on the description:

• remove HTML comments which are often added by the 'Generate release notes' button
• trim the resulting description
• reduce consecutive whitespace/newlines into a minimum of 2 to allow separation in paragraphs
• parse common Github URLs to more appropriate display
• add options:
  • max_description: Discord allows a max of 4096, so allow for more but prevent from going over with ellipses and link "buffer"
  • reduce_headings: Enabling this will actually perform what looks like was intended of converting H2's to bold and H3's to bold and underline for a more reduced display. I left it defaulted at false to mimic it's current state which didn't seem to actually perform the heading conversion. I couldn't find a reason why the original code wasn't performing the heading conversion, but the new regex does work.

[rhullah]

@SethCohen, any chance of getting this merged in?