* sh doesn't allow nesting of prefix strip
* also update some minor test profile bits
* new AMI revisions (fixed nvme)
* edge AMI release should remain a timestamp
* switch build name from 'current-x86_64' to 'v#_#-x86_64' to avoid any confusion when new versions roll out
* resolvie-alpine.py.in - only warn about disabled regions once, instead of for each profile build
* make-amis - tweak script output
* new set of AMIs for edge, 3.10.0, and 3.9.4
* Makefile - improve/fix check for required make vars
* resolve-profile.py.in
+ build a list of all regions & probe to see which ones are enabled (unknown if special subscription regions like ap-northeast-3 would show up in this list)
+ expand 'ami_regions' 'ALL' meta key to all enabled regions, 'ALL' key's value is preserved (that is, a value of None or False will disable all regions)
+ warn/remove regions in profile config that are found to be disabled.
+ improve checks for [None, False] values
* Build Profiles (completion of PR #49)
+ auto-updates version profile when new release detected
+ updates releases/<profile>.yaml after successful builds
* Prune AMIs (in AWS and in releases/<profile>.yaml
+ 'revision' - keep latest revision per release
+ 'release' - keep latest release per version
+ 'version' - remove end-of-life versions
* releases/README.md updater script
* README overhaul
+ Pre-built AMIs --> releases/README.md
+ profiles/README.md for profile configuration details
+ main README.md overhauled to go over how to build and manage custom AMIs
