chore(build) Add support for building with Fedora 44

[rahst12]

Description

• Fixed

  • fix(build): detect jemalloc under /usr/lib64 so a dnf-installed jemalloc-devel is found on
    Fedora/RHEL multilib systems
  • fix(build): compile the bundled jemalloc 5.3.1 with --disable-cxx to avoid the
    std::__throw_bad_alloc build failure on GCC 13+ (e.g. Fedora 44 / GCC 15); dgraph only links
    jemalloc's C API, so the C++ layer is not needed
  • fix(build): chain the jemalloc build recipe with && (was ;) so a failed compile no longer
    falls through to make install, and clear any stale /tmp/jemalloc-temp before rebuilding
  • fix(test): add the Docker CE repo via a downloaded .repo file instead of
    dnf config-manager --add-repo, which was removed in DNF5 (Fedora 41+) and broke
    make setup on Fedora

• Added

  • test: add contrib/smoke-test.sh to bring up a local zero+alpha and verify
    schema/mutation/query against a freshly built binary

• Changed

  • build: linux-dependency now auto-detects the package manager (apt/dnf/pacman) and installs the
    C/C++ toolchain + protobuf-compiler, so build prerequisites work on Fedora/RHEL and Arch in
    addition to Debian/Ubuntu

• Docs

  • docs(contributing): document building Dgraph on Fedora/RHEL

Checklist

• The PR title follows the
  Conventional Commits syntax, leading
  with fix:, feat:, chore:, ci:, etc.
• Code compiles correctly and linting (via trunk) passes locally
• Tests added for new functionality, or regression tests for bug fixes added as applicable
• [-] For public APIs, new features, etc., a PR on the
  docs repo staged and linked here. This process can
  be simplified by going to the public docs site and clicking the
  "Edit this page" button at the bottom of page(s) relevant to your changes. Ensure that you
  indicate in the PR that this is an unreleased feature so that it does not get merged into
  the main docs prematurely.

Instructions

• The PR title should follow the
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  with a !. For instance, feat(dql)!: Remove the foobar func would indicate that this is a
  breaking change to the DQL syntax.
• The description should briefly explain what the PR is about. In the case of a bugfix, describe or
  link to the bug.
• In the checklist section, check the boxes in that are applicable, using [x] syntax.
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Thank you for your contribution to Dgraph!