Introduce teal_data class

[gogonzo]

Couple of fixes needed to use qenv in other packages:

https://cran.r-project.org/doc/manuals/R-exts.html#Namespaces-with-S4-classes-and-methods

[github-actions]

Code Coverage Summary

Filename                     Stmts    Miss  Cover    Missing
-------------------------  -------  ------  -------  ------------------------
R/include_css_js.R               7       7  0.00%    12-20
R/qenv-concat.R                 10       0  100.00%
R/qenv-constructor.R            12       0  100.00%
R/qenv-eval_code.R              49       2  95.92%   95, 104
R/qenv-get_code.R               18       0  100.00%
R/qenv-get_var.R                19       0  100.00%
R/qenv-get_warnings.R           24       0  100.00%
R/qenv-join.R                   46       0  100.00%
R/qenv-show.R                    1       1  0.00%    16
R/qenv-within.R                  7       0  100.00%
R/utils-code_dependency.R      190       7  96.32%   37, 42, 252-253, 317-320
R/utils.R                       12       0  100.00%
TOTAL                          395      17  95.70%

Diff against main

Filename      Stmts    Miss  Cover
----------  -------  ------  --------
TOTAL             0       0  +100.00%

Results for commit: 6806394

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results

[github-actions]

Unit Tests Summary

    1 files    10 suites   1s ⏱️
  92 tests   92 ✔️ 0 💤 0 ❌
186 runs  186 ✔️ 0 💤 0 ❌

Results for commit 6806394.

♻️ This comment has been updated with latest results.

[pawelru]

Please add NEWS

[vedhav]

LGTM

[chlebowa]

methods::new is no longer needed then, is it?

[gogonzo]

methods::new is no longer needed then, is it?
True. Not needed, but not suggested to do otherwise neither