TOOLS-1120 Add option targetDb to mongorestore when use option archive

[ArthurHlt]

When we use the option archive it could be nice to de-archive just one database inside another database which have a different name.

The actual use case is this one:

1. I have a mongo database created by a SaaS, this service give one database
2. I dump this database as an archive (Archive is used because of the necessity to dump it as a stream using stdout)
3. I want to restore my database to a new created database created from SaaS wich have a different database name than the original one
4. I'm blocked cause it's not possible with --archive option when restoring, it wants to create a database with the name from the original database which is not possible to use

Behavior of the option --targetDb in mongorestore:

• this can only be used when using --archive option
• This option make mongorestore to restore just one database at once
• If you have more than one database in archive and user use --targetDb it will fail, in this case it will ask to set also the option --db
• else mongorestore will take the only database set in archive and restore it in the database set in --targetDb

For the test, i didn't any test cause I don't see ad to add them, it seems to have no canvas to make this test. It should be in mongorestore_test.go but there is no relevant place for this because --archive option doesn't seem to be tested

[bompus]

+1 to have this fixed. Didn't fully review the PR, but the core problem needs to be solved either way.

[lorepozo]

We've implemented a solution to this, via TOOLS-1234 documented by DOCS-8118. This added namespace inclusion, exclusion, and renaming support. These new CLI options are prefixed with ns because they take a namespace pattern (where asterisks must be escaped for literal use). For example:

# restore everything, but rename prod db to staging
$ mongorestore --nsFrom 'prod.*' --nsTo 'staging.*' --archive='my_archive'
# restore only prod db, and rename it
$ mongorestore --nsInclude 'prod.*' --nsFrom 'prod.*' --nsTo 'staging.*' --archive='my_archive'
# restore everything but the prod db
$ mongorestore --nsExclude 'prod.*' --archive='my_archive'

These changes are committed at 77d72c8.