feat(vector): add basic functions (vector/vector_extract etc)

[sivukhin]

Context

This PR adds native support for vector functions in the LibSQL.

This PR were extracted from the branch https://github.com/tursodatabase/libsql/pull/1402/ in order to make review more granular and simpler

• Vectors are represented as binary blobs with vector components encoded in little-endian format according to IEEE-754 standard
  • LibSQL now supports f32/f64 vectors of any dimension not more than 65536 (see MAX_VECTOR_SZ)
  • Zero-length vectors are supported - and they are always represented as zero size BLOB (not NULL)
• LibSQL can extended vector encoding on disk with 1 trailing byte which will encode vector type information (for now: 1 = F32, 2 = F64).

  [F3 76 86 C4] [BC 9D F1 3F] [01] - this is f32 vector because type equals to 0x01 = 1 (value = [-1075.72,1.88763])
  [F3 76 86 C4] [BC 9D F1 3F]      - this is f32 vector because default type is 1 (value = [-1075.72,1.88763])
  [F3 76 86 C4   BC 9D F1 3F] [02] - this is f64 vector because type equals to 0x02 = 2 (value = [1.10101])

Changes

• 5 new builtin functions are added:
  • vector/vector32/vector64 - convert TEXT or BLOB to binary vector BLOB. If text is provided - then vector/vector32 will produce F32 vector, but vector64 - F64 vector
  • vector_extract - convert binary vector BLOB to the human readable TEXT string (like [1,2,3])
  • vector_distance_cos - calculates cosine distance (not similarity) between vectors of same dimension and same type
• SQLITE_OMIT_VECTOR preprocessor directive and autoconf parameter --disable-vector which will remove any signs of vector functions from the final build
• libsql_vector.test - TCL based test suite

[haaawk]

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found uncommited changes in the bundle; please run 'cargo xtask build-bundled' and commit the result