Summary:
pgrx is a framework for developing PostgreSQL extensions in Rust used by several extensions, for example pg_parquet.

Importing the pgrx framework from https://github.com/pgcentralfoundation/pgrx.git into src/postgres/third-party-extensions/pgrx

v0.14.1 / b1868d8 was chosen as lastest released version(v0.4.0) of pg_parquet depends on v0.14.1 pgrx

Used squash approach instead of subtree due large number of commits in the pgrx repo (over 2000 commits).

Have only removed the .git folder.

Integrating the framework into the build will be done in a subsequent change.

Fixes #27323
Jira: DB-16833

Test Plan: Jenkins

Reviewers: jason, hsunder

Reviewed By: jason

Subscribers: yql

Differential Revision: https://phorge.dev.yugabyte.com/D44595