[patch] Fix HADR in GovCloud

[tomklapiscak]

This PR resolved two separate problems relating to the use of S£ as part of the HADR setup process:

GovCloud Compatibility

S3 URL is different in GovCloud (e.g. https://s3-fips.us-gov-east-1.amazonaws.com vs https://s3.us-east-1.amazonaws.com), which was causing downloads from S3 to fail. This PR fixes this by passing in the value of the SERVER variable in .PROPS to the --endpoint-urlargument of theaws s3 cp` command.

• verify that this works in commercial too

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Issues with large backup files

A subsequent issue was discovered where the db 2RemStgManager command was segfaulting when attempting to upload a large backup file.

I had 2 backup parts: 001 is 25GB, and 002 is 97MB.

The db2RemStgManager command code used to upload backup files to S3 is failing for the 25GB 001 part with:

Memory fault(coredump)

but works fine for the 97MB 002 part.

Not sure why it's failing for the large file only:

• There is sufficient storage in the DB2_OBJECT_STORAGE_LOCAL_STAGING_PATH (>150GB)
• The db2u pod has 32GB memory limit
• No ulimits set on db2inst1 user
• DB2_ENABLE_COS_SDK isn't set (so defaults to `ON), so no file limit of 5GB and multipart upload should be supporteds
• multipartsizemb is set to the default of 100MB

This PR fixes this by replacing the db2RemStgManager command with a simple call to aws s3 cp (which is already used on the standby to download the backup files).