CDRIVER-4730 TLS Backend Cleanup (mongodb#1408)

* Clean up of TLS detection and import
* Earthly TLS controls and cleaner build envs
Adds a --tls build parameter to switch TLS backends. This PR also adds
a "str" utility for doing more concise string manipulation in POSIX sh.
* EVG Earthly tasks for more build configurations
This refactors earthly.py for extensibility and to match the
parameterization used in Earthfile.
* Support "auto" in Earthfile
* Tweak name spacing
* More feature and package summary information
* Unused LibreSSL compat

Author: vector-of-bool

str.sh

@@ -0,0 +1,101 @@
+#!/bin/sh
+
+# This is a tiny shell utility for string manipulation.
+# Allow us to use "local"
+# shellcheck disable=SC3043
+
+set -eu
+
+_HELP='Usage:
+  str {lower,upper}
+  str test
+
+Commands:
+  lower, upper
+    Convert input (stdin) to all-lowercase or all-uppercase, respectively
+
+  test <str1> (-ieq|-ine|-contains|-matches) <str2>
+    Like "test", but with additional string comparisons:
+      -ieq • case-insensitive equal
+      -ine • case-insensitive not-equal
+      -contains • Check if <str1> contains <str2>
+      -matches • Check if <str1> matches pattern <str2> (A grep -E pattern)
+'
+
+fail() {
+  # shellcheck disable=SC2059
+  printf -- "$@" 1>&2
+  printf -- "\n" 1>&2
+  return 1
+}
+
+__str__upper() {
+  __justStdin upper __upper "$@"
+}
+__upper() {
+  tr '[:lower:]' '[:upper:]'
+}
+
+__str__lower() {
+  __justStdin lower __lower "$@"
+}
+__lower() {
+  tr '[:upper:]' '[:lower:]'
+}
+
+__justStdin() {
+  if test $# -gt 2; then
+    fail "Command '%s' does not take any arguments (write input into stdin)" "$1" || return
+  fi
+  "$2"
+}
+
+__str__help() {
+  printf %s "$_HELP"
+}
+__str____help() {
+  __str help
+}
+__str___h() {
+  __str help
+}
+__str___help() {
+  __str help
+}
+
+__str__test() {
+  test "$#" -eq 3 || fail '“str test” expects three arguments (Got %d: “%s”)' $# "$*" \
+    || return
+  local lhs="$1"
+  local op="$2"
+  local rhs="$3"
+  local norm_lhs norm_rhs;
+  norm_lhs=$(echo "$lhs" | __str lower) || return
+  norm_rhs=$(echo "$rhs" | __str lower) || return
+  case $op in
+    -ieq)
+      test "$norm_lhs" = "$norm_rhs";;
+    -ine)
+      test "$norm_lhs" != "$norm_rhs";;
+    -matches)
+      printf %s "$lhs" | grep -qE -- "$rhs";;
+    -contains)
+      printf %s "$lhs" | grep -qF -- "$rhs";;
+    -*|=*)
+      # Just defer to the underlying test command
+      test "$lhs" "$op" "$rhs"
+  esac
+}
+
+__str() {
+  local _Command="$1"
+  local _CommandIdent
+  _CommandIdent="$(echo "__str__$_Command" | sed '
+    s/-/_/g
+    s/\./__/g
+  ')"
+  shift
+  "$_CommandIdent" "$@"
+}
+
+__str "$@"