[R-package] add deprecation warnings about some uses of '...'

[jameslamb]

Contributes to #4310 (based on #4226 (comment)).

This PR proposes adding some deprecation warnings on uses of ... for parameters in the following functions:

• dim.lgb.Dataset()
• getinfo.lgb.Dataset()
• lgb.cv()
• lgb.train()
• setinfo.lgb.Dataset()

Notes for reviewers

Given this R code

library(lightgbm)

data(agaricus.train, package = "lightgbm")
train <- agaricus.train
dtrain <- lgb.Dataset(train$data, label = train$label)

model <- lgb.train(
    params = list(
        objective = "regression"
    )
    , data = dtrain
    , nrounds = 5L
    , bagging_fraction = 0.5
    , bagging_freq = 2L
)

This is the warning shown:

Warning message:
In lgb.train(params = list(objective = "regression"), data = dtrain, :
lgb.train: Found the following passed through '...': bagging_fraction, bagging_freq. These will be used, but in future releases of lightgbm, this warning will become an error. Add these to 'params' instead. See ?lgb.train for documentation on how to call this function.

Deprecation warnings for other uses of ... will be addressed in other pull requests.

[StrikerRUS]

LGTM!

[github-actions]

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