Simplified test case as bit

fix: set `first_response_time` only if communication is sent

fix(ldap): Auto-negotiate the highest TLS protocol version supported by client & server

For consistency

* Made it easier to run locally :')
* Moved content in setupclass rather than class init

fix: clear cache for all docs matched with the filters passed as `dn` param in `set_value`

fix: avoid cached results for `table_exists` during install

Background: Currently, when connecting to a ldap backend, ssl.PROTOCOL_TLSv1 [2] is offered as only option to the backend.

This leads to following issues:
- LDAP Backends that do not support TLSv1.0 (because of security reasons [3]) cannot be used in ERPNext
- erpnext can ONLY connect to LDAP Backends offering the insecure [3] TLSv1.0 protocol  (see ldap_settings.py ln: 61, 63)

With this change to ssl.PROTOCOL_TLS_CLIENT we allow erpnext customers to configure LDAP Backends that also support more modern/secure (TLSv1.2 and up) transport
while still ensure backwards compatibility and allowing TLSv1.0,
since ssl.PROTOCOL_TLS "Auto-negotiates the highest protocol version that both the client and server support" [1]

[1]: https://docs.python.org/3/library/ssl.html#ssl.PROTOCOL_TLS_CLIENT
[2]: https://docs.python.org/3/library/ssl.html#ssl.PROTOCOL_TLSv1
[3]: https://tools.ietf.org/id/draft-ietf-tls-oldversions-deprecate-02.html

fix: Revert breaking API change in Assign To

fix(blog): Load more with category filter

fix(postgres)!: transactions implementation for PostgreSQL

When you click "Load more" on a blog category page, it will now fetch blog posts for that category

fix: Constant fields for documents

fix: Remove internal owner field used in existing tables

feat(minor): copy link to clipboard

To implement repeatable reads it has to respect transactions.

RR isolation is default in MariaDB, for sake of consistency use same
isolation level in postgres

feat: Fixed the dilemma of owner field in ToDo document