Remove residual code and their dependencies

[vedhav]

Closes #158

[github-actions]

Code Coverage Summary

Filename                 Stmts    Miss  Cover    Missing
---------------------  -------  ------  -------  ---------
R/qenv-concat.R             10       0  100.00%
R/qenv-constructor.R        12       0  100.00%
R/qenv-eval_code.R          52       2  96.15%   100, 109
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-replace_code.R        8       0  100.00%
R/qenv-show.R                1       1  0.00%    16
R/qenv-within.R              7       0  100.00%
R/utils.R                   12       0  100.00%
TOTAL                      209       3  98.56%

Diff against main

Filename      Stmts    Miss  Cover
----------  -------  ------  -------
TOTAL             0       0  +3.19%

Results for commit: d5fd78b

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results

[github-actions]

Unit Tests Summary

    1 files    10 suites   0s ⏱️
  75 tests   75 ✔️ 0 💤 0 ❌
161 runs  161 ✔️ 0 💤 0 ❌

Results for commit d5fd78b.

[kartikeyakirar]

LGTM 👍