Refactor update_libchdb.sh for system-wide install and improve README

[JakkuSakura]

This PR fixes deps so that it can use system-wide libchdb

The download script is tailored from https://clickhouse.com/docs/chdb/install/rust

[CLAassistant]

All committers have signed the CLA.

[auxten]

Pipeline failed, should be the same issue here chdb-io/chdb#318

[auxten]

The issue here is complex:

1. chdb-rust is still using libchdb v2 API, and there are many unresolvable problems with session state or persistence. The main issue here is that the query function in libchdb v2 undergoes complete state recovery and system table initialization with each call. Therefore, the previous version locked chdb-rust's libchdb usage to v2.1.1.
2. We have completed the upgrade of chdb Python binding, using connection-based API to circumvent the above issues, but chdb-rust has not yet completed the restructuring based on chdb v3.

Here is the action plan:

1. First, complete the pipeline repair based on libchdb v2
2. Complete the restructuring of chdb-rust based on libchdb v3.
3. Merge this PR, as the modifications to update_libchdb.sh and README in this PR are very valuable.

[auxten]

I fix the pipeline by fix libchdb to v2.1.1, as the pipeline recover now. I will merge the PR, then the tasks left is:

1. Complete the restructuring of chdb-rust based on libchdb v3.

@JakkuSakura Thanks for your contribution, and sorry for the trouble 🙏