python3.pkgs.jinja2: don't build offline documentation by default

E.g. `systemd` fails like this:

last 25 log lines:
> Checking for function "blkid_probe_set_hint" with dependency blkid: YES
> Run-time dependency libkmod found: YES 30
> Run-time dependency xencontrol found: NO (tried pkgconfig and cmake)
> Run-time dependency libmicrohttpd found: NO (tried pkgconfig and cmake)
> Checking for function "crypt_activate_by_token_pin" : NO
> Run-time dependency libiptc found: NO (tried pkgconfig and cmake)
> Run-time dependency libqrencode found: NO (tried pkgconfig and cmake)
> Run-time dependency gnutls found: NO (tried pkgconfig and cmake)
> Run-time dependency openssl found: NO (tried pkgconfig, system and cmake)
> Run-time dependency p11-kit-1 found: NO (tried pkgconfig and cmake)
> Run-time dependency tss2-esys tss2-rc tss2-mu found: NO (tried pkgconfig and cmake)
> Run-time dependency libdw found: NO (tried pkgconfig and cmake)
> Run-time dependency zlib found: NO (tried pkgconfig, cmake and system)
> Library bz2 found: NO
> Run-time dependency liblzma found: NO (tried pkgconfig and cmake)
> Run-time dependency libzstd found: NO (tried pkgconfig and cmake)
> Run-time dependency xkbcommon found: NO (tried pkgconfig and cmake)
> Run-time dependency libpcre2-8 found: NO (tried pkgconfig and cmake)
> Run-time dependency dbus-1 found: NO (tried pkgconfig and cmake)
> Message: default-dnssec cannot be set to yes or allow-downgrade openssl and gcrypt are disabled. Setting default-dnssec to no.
> Program python3 (jinja2) found: NO
>
> meson.build:1949:15: ERROR: python3 is missing modules: jinja2

Upon trying more packages I realized that this is not the only one (it
appears to be related to `python3.withPackages` in some cases).

For now, flip the default to unbreak a lot of stuff and remove the
`enableDocumentation = false;` hacks from a bunch of other packages.

pkgs/applications/misc/privacyidea/default.nix

···
         doCheck = false;
       });
       # Required by flask-1.1
-      jinja2 = (super.jinja2.override { enableDocumentation = false; }).overridePythonAttrs (old: rec {
+      jinja2 = super.jinja2.overridePythonAttrs (old: rec {
         version = "2.11.3";
         src = old.src.override {
           inherit version;

pkgs/development/python-modules/jinja2/default.nix

···
 , pallets-sphinx-themes
 , sphinxcontrib-log-cabinet
 , sphinx-issues
-, enableDocumentation ? true
+, enableDocumentation ? false
 }:
 
 buildPythonPackage rec {

pkgs/development/python-modules/sphinx/default.nix

···
     alabaster
     docutils
     imagesize
-    (jinja2.override { enableDocumentation = false; })
+    jinja2
     packaging
     pygments
     requests