[hotfix] toolchain tweaks for bugless fresh deploys

assorted toolchain bug fixes gleaned from making a fresh deploy of a fresh instance of sb for pentesting...

ensure ACMEv2 support in letsencrypt companion

• LE dropped support for ACMEv1 late last year
• to ensure we are running a version of the letsencrypt companion docker container that uses ACMEv2 we need to pull the latest version
• see: https://github.com/nginx-proxy/docker-letsencrypt-nginx-proxy-companion/issues/598

set postgres auth method to trust

• necessary for compatibility w/ newer versions of dockerized postgres
• see: https://github.com/docker-library/postgres/issues/692

stop check-availability from always giving false positive

• due to syntax error in conditional check, bash script was failing silently and returning success on first check, which often was failing
• fix this by using double brackets instead of single ones. (isn't bash the best?)