iceberg: add simple drop_table support for filesystem_catalog

[ztlpn]

This implementation leaves data files as orphans, but is enough for trying iceberg out.

Backports Required

• none - not a bug fix
• none - this is a backport
• none - issue does not exist in previous branches
• none - papercut/not impactful enough to backport
• v24.3.x
• v24.2.x
• v24.1.x

Release Notes

• none

[bharathv]

lgtm

[ztlpn]

unrelated bazel failures:

FAIL: //src/v/raft/tests:stm_manager_test (run 1 of 3) (see /root/.cache/bazel/_bazel_root/faeef8fde5e6a20d63d83890c1f75a45/execroot/_main/bazel-out/k8-fastbuild/testlogs/src/v/raft/tests/stm_manager_test/run_1_of_3/test.log)
...
FAIL: //src/v/raft/tests:raft_reconfiguration_test (run 1 of 3) (see /root/.cache/bazel/_bazel_root/faeef8fde5e6a20d63d83890c1f75a45/execroot/_main/bazel-out/k8-fastbuild/testlogs/src/v/raft/tests/raft_reconfiguration_test/run_1_of_3/test.log)

[vbotbuildovich]

/backport v24.3.x

[vbotbuildovich]

Failed to create a backport PR to v24.3.x branch. I tried:

git remote add upstream https://github.com/redpanda-data/redpanda.git
git fetch --all
git checkout -b backport-pr-24299-v24.3.x-690 remotes/upstream/v24.3.x
git cherry-pick -x 3476abdfc6 2b469d146c 5cf96dfb37 049dd7d4a4

Workflow run logs.

[rockwotj]

/backport v24.3.x