Remove pkg --check-activation. It is too tempting to use.

We cannot accept anyone using this as a valid check. Accidental
bootstraps are frustrating for users.
Make it more clear that the 'Major version' change is non-fatal
Jobs display: Avoid excessive newline before prompt and after unprompted usage
Followup 4bc7073308cb and remove references to PACKAGESITE/MIRROR_TYPE/PUBKEY
Support uppercase ENABLED in repo config.

This is a partial fix. It would be better to store all keys
as lowercase or uppercase. Other variables are affected by
this.

Issue:	#960
Avoid POLA, make PACKAGESITE/MIRROR_TYPE/PUBKEY in pkg.conf fatal
Fix self upgrade loop, again, with pkg upgrade -Fy

Issue:	#962
Fix self upgrade not using the new pkg binary

Verified this works with -j still.

Issue:	#954