Merge !6787: Shell & plugins: bound the mempool by op count and total byte size

Context

Un-revert !6787 (merged). It was reverted in !8769 (merged) because of a suspicion that it may have caused CI problems. However, the CI problems have persisted after the revert.

Created with git cherry-pick 89e8c7a8 -m 1. There were no conflicts to resolve manually:

Auto-merging CHANGES.rst
Auto-merging manifest/main.ml
Auto-merging tezt/tests/dune
[detached HEAD 4f6d6f624a] Merge tezos/tezos!6787: Shell & plugins: bound the mempool by op count and total byte size
 Author: Marge Bot <marge-bot@nomadic-labs.com>
 Date: Mon May 15 08:56:40 2023 +0000
 64 files changed, 3273 insertions(+), 4102 deletions(-)
 create mode 100644 src/lib_shell/prevalidator_bounding.ml
 create mode 100644 src/lib_shell/prevalidator_bounding.mli
 create mode 100644 src/lib_shell/test/test_prevalidator_bounding.ml
 create mode 100644 src/proto_016_PtMumbai/lib_plugin/mempool.mli
 delete mode 100644 src/proto_016_PtMumbai/lib_plugin/test/generators.ml
 delete mode 100644 src/proto_016_PtMumbai/lib_plugin/test/test_filter_state.ml
 delete mode 100644 src/proto_016_PtMumbai/lib_plugin/test/test_plugin.ml
 delete mode 100644 src/proto_016_PtMumbai/lib_plugin/test/test_utils.ml
 create mode 100644 src/proto_017_PtNairob/lib_plugin/mempool.mli
 delete mode 100644 src/proto_017_PtNairob/lib_plugin/test/generators.ml
 delete mode 100644 src/proto_017_PtNairob/lib_plugin/test/test_filter_state.ml
 delete mode 100644 src/proto_017_PtNairob/lib_plugin/test/test_plugin.ml
 delete mode 100644 src/proto_017_PtNairob/lib_plugin/test/test_utils.ml
 create mode 100644 src/proto_alpha/lib_plugin/mempool.mli
 delete mode 100644 src/proto_alpha/lib_plugin/test/generators.ml
 delete mode 100644 src/proto_alpha/lib_plugin/test/test_filter_state.ml
 delete mode 100644 src/proto_alpha/lib_plugin/test/test_plugin.ml
 delete mode 100644 src/proto_alpha/lib_plugin/test/test_utils.ml

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR