Update features / enhancements repo documentation

[justaugustus]

Include:

• create glossary #2517
• issue templates
  • enhancements
    • standard
    • API changes
• create PR templates #2518
• exceptions process update #2519

Work item for #617

/kind feature
/sig pm
/milestone v1.13
/assign

[ameukam]

@justaugustus Can i take care of this ?

[justaugustus]

@ameukam -- absolutely; would love the help! Please ping me on the PR once you have a chance to work on it. :)
/assign @ameukam

[luxas]

This is done now?

[spiffxp]

/milestone clear
ref #617 (comment)

[justaugustus]

/milestone v1.14

[justaugustus]

/remove-milestone v1.14
/milestone keps-beta