postgresql_query: deprecate and remove script related options and return values in favor of using postgresql_script module in 3.0.0

[Andersson007]

SUMMARY

Relates to #188
Relates to the discussion in #180 (comment)

postgresql_query: deprecate and remove script related options and return values in favor of using postgresql_script module in community.postgresql 3.0.0:

• options: path_to_script and as_single_query
• ret values: query_list and query_all_results

The rough plan is:

• Merge postgresql_script module. Done postgresql_script: new module #188
• Add a deprecation warning to the postgresql_query module about deprecation of the path_to_script and as_single_query options and related ret values. The warning will ask users to use the postgresql_script module postgresql_query: deprecate script related options and return values #190
• Update docs in the postgresql_query module postgresql_query: deprecate script related options and return values #190
• Announce the deprecation and removal in the next major release (6 months - 1 year) postgresql_query: deprecate script related options and return values #190
• Release the above
• Move functions shared between postgresql_query and postgresql_script to module_utils/postgres.py and import them from there.
• In 6 months - 1 year plan release 3.0.0
• Remove the options and values right before the release 3.0.0 commit
• Release 3.0.0