Dynamically find python in meson build.

This is better than requiring a python3 binary to be on the path because some installations might have, e.g. python3.9.

Also add the python3-distutils package to Debian builds to make this work.

test/ci.pl

@@ -182,7 +182,7 @@ eval
     {
         # Build list of packages that need to be installed
         my $strPackage =
-            "gcc ccache python3-pip git rsync zlib1g-dev libssl-dev libxml2-dev libpq-dev libyaml-dev pkg-config uncrustify" .
+            "gcc ccache python3-distutils git rsync zlib1g-dev libssl-dev libxml2-dev libpq-dev libyaml-dev pkg-config uncrustify" .
             " libssh2-1-dev valgrind";
 
         # Add lcov when testing coverage

test/container.yaml

@@ -12,10 +12,13 @@
 # - docker login -u pgbackrest
 # - VM=XXX;DATE=YYYYMMDDX;BASE=pgbackrest/test:${VM?}-base;docker tag ${BASE?} ${BASE?}-${DATE?} && docker push ${BASE?}-${DATE?}
 # **********************************************************************************************************************************
+20240425A:
+  x86_64:
+    d10: fb03907abefd68fe16557b759e7e110e99eda748
+    u20: c3fc7cc1956c5eb10995119deed7a21b92dd07a7
+    u22: 11cead06a18450f45518b386181a4b7e8ffaf4c1
+
 20240423A:
   x86_64:
-    d10: e0f7a22cefb28f36d5c4f53b306ce76cd22a55b1
     f38: 6f15d0dd72891c84b6ef5697cbe4b1c7e95c57cb
     rh7: 3ba01dc5bbc96eed48287b8e4f52054d4d7030a5
-    u20: c75f3d16e66aefb847da47eacb5c5e2595b582a5
-    u22: 5d9d1cf2d1df9f20fae8e1edda93bd41e3d38626

test/lib/pgBackRestTest/Common/ContainerTest.pm

@@ -408,7 +408,7 @@ sub containerBuild
                 "    export DEBCONF_NONINTERACTIVE_SEEN=true DEBIAN_FRONTEND=noninteractive && \\\n" .
                 "    apt-get update && \\\n" .
                 "    apt-get install -y --no-install-recommends openssh-server wget sudo gcc make valgrind git \\\n" .
-                "        libdbd-pg-perl libhtml-parser-perl libssl-dev libperl-dev \\\n" .
+                "        libdbd-pg-perl libhtml-parser-perl libssl-dev libperl-dev python3-distutils \\\n" .
                 "        libyaml-libyaml-perl tzdata devscripts lintian libxml-checker-perl txt2man debhelper \\\n" .
                 "        libppi-html-perl libtemplate-perl libtest-differences-perl zlib1g-dev libxml2-dev pkg-config \\\n" .
                 "        libbz2-dev bzip2 libyaml-dev libjson-pp-perl liblz4-dev liblz4-tool gnupg lsb-release ccache meson \\\n" .