pgAdmin 4 commit: Added 'IF NOT EXISTS' clause while creating tables an

Added 'IF NOT EXISTS' clause while creating tables and partition tables which is convenient while using the ERD tool.
Fixes#6397 

Branch
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master

Details
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https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=7e79814cb0a308364a2f6e1b62efee32989e8435

Modified Files
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docs/en_US/release_notes_5_3.rst                                        | 1 +
.../schemas/tables/templates/partitions/sql/pg/10_plus/create.sql       | 2 +-
.../schemas/tables/templates/partitions/sql/ppas/10_plus/create.sql     | 2 +-
.../databases/schemas/tables/templates/tables/sql/10_plus/create.sql    | 2 +-
.../databases/schemas/tables/templates/tables/sql/11_plus/create.sql    | 2 +-
.../databases/schemas/tables/templates/tables/sql/12_plus/create.sql    | 2 +-
.../databases/schemas/tables/templates/tables/sql/9.6_plus/create.sql   | 2 +-
.../databases/schemas/tables/templates/tables/sql/default/create.sql    | 2 +-
8 files changed, 8 insertions(+), 7 deletions(-)