121 create a dm_explicit_na for preprocessing.

[BFalquet]

close #121

new function to make the life of the tester easier by considerably reducing the manual steps involved in data preparation.
thank you for the review

[github-actions]

Code Coverage Summary

Filename                           Stmts    Miss  Cover    Missing
-------------------------------  -------  ------  -------  ---------
R/aet02.R                            163     163  0.00%    55-418
R/aet03.R                             61      61  0.00%    44-145
R/aet04.R                             67      67  0.00%    53-159
R/assertthat.R                         1       1  0.00%    3
R/cmt01a.R                           132     132  0.00%    49-367
R/dm_explicit_na.R                    44      44  0.00%    46-133
R/dmt01.R                             20      20  0.00%    48-113
R/dst01.R                            203     203  0.00%    5-542
R/egt01.R                             39      39  0.00%    47-126
R/ext01.R                             41      41  0.00%    40-176
R/gen_args.R                           1       1  0.00%    18
R/lbt01.R                             34      34  0.00%    43-111
R/mht01.R                             52      52  0.00%    42-126
R/sample_study_object.R               12      12  0.00%    15-34
R/standard_data_preprocessing.R      117     117  0.00%    35-382
R/utils.R                            136     136  0.00%    17-396
R/vst01.R                             40      40  0.00%    48-128
TOTAL                               1163    1163  0.00%

Results for commit: 8248ac8d5aee37f7240d28f6780412278cebd91f

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results

[barnett11]

This works really well for me thanks @BFalquet .

As discussed, depending how we foresee this being used in future it may be necessary to have a select_tables in contrast to the omit_tables option if potentially users want to use on specific datasets for the template only (rather than the entire dm), but fine for now

[wangh107]

👍