Add exact-match to etlr options

[pabloarosado]

Following the discussion in #3197 I think we should have an exact-match option in etlr, to run steps that happen to be substrings of other steps (e.g. data://grapher/war/2023-09-21/ucdp, substring of data://garden/war/2023-09-21/ucdp_prio).

Currently etlr data://garden/war/2023-09-21/ucdp --only --dry-run --force:

--- Would run 2 steps:
1. data://garden/war/2023-09-21/ucdp
2. data://garden/war/2023-09-21/ucdp_prio

And if you want to run only the desired step you need to do etlr data://garden/war/2023-09-21/ucdp$ --only --dry-run --force, which is a bit of a hack. To avoid such unexpected executions, users not only need to remember this hack, but also know that there are other steps that will be matched to the given argument.

Instead, this PR lets you do etlr data://garden/war/2023-09-21/ucdp --only --exact-match --dry-run --force:

--- Would run 1 steps:
1. data://garden/war/2023-09-21/ucdp

[owidbot]

Quick links (staging server):

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Login: ssh owid@staging-site-add-exact-match-to-etlr

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Hint: Run this locally with etl diff REMOTE data/ --include yourdataset --verbose --snippet

Automatically updated datasets matching weekly_wildfires|excess_mortality|covid|fluid|flunet|country_profile|garden/ihme_gbd/2019/gbd_risk are not included

Edited: 2024-08-27 08:26:28 UTC
Execution time: 12.38 seconds

[Marigold]

The PR looks good, but I wouldn't say that using $ is a hack :).