feat: add key prefix count assertions to transactions

[drmingdrmer]

I hereby agree to the terms of the CLA available at: https://docs.databend.com/dev/policies/cla/

Summary

feat: add key prefix count assertions to transactions

Enable transaction conditions based on the number of keys matching a prefix.
Example:

let txn = TxnRequest {
    condition: vec![ TxnCondition::match_keys_with_prefix("key/", Eq, 3) ],
    //...
}

This allows transactions to proceed only when a prefix matches an expected
number of keys, providing atomic prefix-based cardinality checks.

This commit involves a databend-meta server side change:

• Add txn_condition::Target::KeysWithPrefix.

To provide compatibility, any change to the client that uses this
feature must update the compatibility doc and upgrade the databend-meta
cluster first.

MM src/meta/kvapi/src/kvapi/test_suite.rs

Tests

• Unit Test
• Logic Test
• Benchmark Test
• No Test - Explain why

Type of change

• New Feature (non-breaking change which adds functionality)

Related Issues

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This change is 

[what-the-diff]

PR Summary

• Enhanced Documentation: The documentation within our codebase, specifically in lib.rs, has been revised and updated, providing a clearer understanding of our latest features and changes.
• New Feature for Checking Key Quantity: We've integrated a new method kv_transaction_condition_keys_with_prefix, which will allow us to identify the number of keys that correlate to a specific prefix.
• Enhancements in Handling Conditions: We've modified the internal structure of TxnCondition to now offer support in comparing the count of keys using a given prefix.
• Improved Condition Assessment: The evaluation process for conditions in applier.rs has been simplified, enabling different kinds of conditions to be assessed using a singular function.
• Comprehensive Test Adjustments: We updated the test cases to validate the new capabilities of the key count conditions, ensuring a full coverage for the new feature.
• Refinement in Byte Conversion: We've transitioned the conversion method of bytes to a broader application, now accepting any type convertible into a string.