Remove CONTAINER keyword

[frode-aarstad]

Issue
Resolves #3747

Approach
Short description of the approach

Pre review checklist

• Added appropriate release note label
• PR title captures the intent of the changes, and is fitting for release notes.
• Commit history is consistent and clean, in line with the contribution guidelines.

Adding labels helps the maintainers when writing release notes. This is the list of release note labels.

[codecov-commenter]

Codecov Report

Merging #3834 (c17f6ba) into main (f7f669c) will increase coverage by 0.20%.
The diff coverage is 72.72%.

@@            Coverage Diff             @@
##             main    #3834      +/-   ##
==========================================
+ Coverage   63.85%   64.06%   +0.20%     
==========================================
  Files         595      593       -2     
  Lines       44580    44378     -202     
  Branches     4012     3977      -35     
==========================================
- Hits        28467    28431      -36     
+ Misses      14873    14719     -154     
+ Partials     1240     1228      -12     

Impacted Files	Coverage Δ
src/clib/lib/enkf/config_keys.cpp	0.84% <ø> (+<0.01%)	⬆️
src/clib/lib/enkf/enkf_state.cpp	22.48% <ø> (-0.37%)	⬇️
src/clib/lib/enkf/ensemble_config.cpp	38.11% <ø> (+1.02%)	⬆️
...rc/ert/_c_wrappers/enkf/config/enkf_config_node.py	75.90% <ø> (-1.08%)	⬇️
src/ert/_c_wrappers/enkf/data/enkf_node.py	86.95% <ø> (-0.15%)	⬇️
src/ert/_c_wrappers/enkf/ensemble_config.py	90.98% <ø> (-0.43%)	⬇️
...c/ert/_c_wrappers/enkf/enums/ert_impl_type_enum.py	100.00% <ø> (ø)
src/clib/lib/enkf/enkf_node.cpp	41.95% <25.00%> (+4.00%)	⬆️
src/clib/lib/enkf/enkf_config_node.cpp	51.31% <100.00%> (+3.92%)	⬆️
src/clib/lib/enkf/enkf_state_nodes.cpp	57.14% <100.00%> (+7.14%)	⬆️
... and 10 more

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[dafeda]

Did a quick search for CONTAINER in your branch and got two hits, on in config_keys.hpp and one in enkf_types.hpp.
I think we can get rid of those as well.

[oyvindeide]

Did you check if the failing workflow is related to the changes in this PR?

[frode-aarstad]

Did you check if the failing workflow is related to the changes in this PR?

I believe they are historical problems. Seems like clang-tidy runs on the files touched in the PR and reports old issues. Can have a look and see if they are easily solvable

[oyvindeide]

LGTM! Good job cleaning! The file causing the annotation to fail will be removed in #3843 so no need to do anything about it in this PR.