Remove Boost.StaticAssert submodule

Since Boost.StaticAssert has been [merged](https://github.com/boostorg/config/pull/531) into Boost.Config, this submodule can be removed once all Boost libraries have removed references to it. For tracking purposes, here is the list of the relevant PRs:

- https://github.com/boostorg/accumulators/pull/67
- https://github.com/boostorg/algorithm/pull/130
- https://github.com/boostorg/align/pull/24
- https://github.com/boostorg/assert/pull/44
- https://github.com/boostorg/assign/pull/50
- https://github.com/boostorg/array/pull/30
- https://github.com/boostorg/beast/pull/3074
- https://github.com/boostorg/bimap/pull/51
- https://github.com/boostorg/callable_traits/pull/201
- https://github.com/boostorg/charconv/pull/287
- https://github.com/boostorg/chrono/pull/81
- https://github.com/boostorg/circular_buffer/pull/54
- https://github.com/boostorg/cobalt/pull/262
- https://github.com/boostorg/compute/pull/898
- https://github.com/boostorg/concept_check/pull/47
- https://github.com/boostorg/config/pull/533
- https://github.com/boostorg/contract/pull/41
- https://github.com/boostorg/date_time/pull/250
- https://github.com/boostorg/endian/pull/60
- https://github.com/boostorg/function/pull/57
- https://github.com/boostorg/function_types/pull/19
- https://github.com/boostorg/fusion/pull/279
- https://github.com/boostorg/geometry/pull/1447
- https://github.com/boostorg/gil/pull/786
- https://github.com/boostorg/graph/pull/450
- https://github.com/boostorg/graph_parallel/pull/45
- https://github.com/boostorg/hash2/pull/46
- https://github.com/boostorg/heap/pull/57
- https://github.com/boostorg/histogram/pull/419
- https://github.com/boostorg/icl/pull/52
- https://github.com/boostorg/interval/pull/48
- https://github.com/boostorg/io/pull/17
- https://github.com/boostorg/iostreams/pull/190
- https://github.com/boostorg/lexical_cast/pull/95
- https://github.com/boostorg/lockfree/pull/126
- https://github.com/boostorg/math/pull/1351
- https://github.com/boostorg/metaparse/pull/22
- https://github.com/boostorg/move/pull/63
- https://github.com/boostorg/mp11/pull/112
- https://github.com/boostorg/mpi/pull/177
- https://github.com/boostorg/mpl/pull/91
- https://github.com/boostorg/mqtt5/pull/46
- https://github.com/boostorg/multi_array/pull/42
- https://github.com/boostorg/multi_index/pull/91
- https://github.com/boostorg/mysql/pull/497
- https://github.com/boostorg/odeint/pull/105
- https://github.com/boostorg/pfr/pull/229
- https://github.com/boostorg/phoenix/pull/125
- https://github.com/boostorg/program_options/pull/155
- https://github.com/boostorg/property_map/pull/36
- https://github.com/boostorg/property_map_parallel/pull/4
- https://github.com/boostorg/property_tree/pull/134
- https://github.com/boostorg/proto/pull/39
- https://github.com/boostorg/ptr_container/pull/44
- https://github.com/boostorg/python/pull/509
- https://github.com/boostorg/random/pull/152
- https://github.com/boostorg/range/pull/162
- https://github.com/boostorg/rational/pull/57
- https://github.com/boostorg/redis/pull/386
- https://github.com/boostorg/regex/pull/269
- https://github.com/boostorg/serialization/pull/340
- https://github.com/boostorg/signals2/pull/84
- https://github.com/boostorg/smart_ptr/pull/122
- https://github.com/boostorg/sort/pull/109
- https://github.com/boostorg/spirit/pull/846
- https://github.com/boostorg/stacktrace/pull/223
- https://github.com/boostorg/statechart/pull/27
- https://github.com/boostorg/system/pull/139
- https://github.com/boostorg/test/pull/474
- https://github.com/boostorg/thread/pull/417
- https://github.com/boostorg/tuple/pull/32
- https://github.com/boostorg/type_traits/pull/203
- https://github.com/boostorg/typeof/pull/27
- https://github.com/boostorg/ublas/pull/198
- https://github.com/boostorg/units/pull/66
- https://github.com/boostorg/unordered/pull/341
- https://github.com/boostorg/uuid/pull/192
- https://github.com/boostorg/variant/pull/115
- https://github.com/boostorg/wave/pull/245
- https://github.com/boostorg/xpressive/pull/29

- https://github.com/boostorg/boostdep/pull/33
- https://github.com/boostorg/cmake/pull/103
- https://github.com/boostorg/boost-ci/pull/313

Once these PRs are merged and propagate to master, I propose to add a release note for the next Boost release to notify users that the submodule is deprecated and will soon be removed. Then, after 3 Boost releases, actually remove the submodule.

CC @pdimov

Bắt đầu bằng cách kiểm tra thư viện Boost được liên kết, boostdep, cmake và các PR của boost-ci, cũng như việc các thay đổi của chúng đã được đưa vào master hay chưa. Xác nhận rằng tất cả các tham chiếu được liệt kê đã biến mất trước khi thực hiện chuỗi release-note và ba bản release được đề xuất; việc hoàn tất là xóa submodule sau khoảng thời gian chờ đó.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.