Add ignore() option to assert commands

[arthur-shaw]

User story

After discovering offending variables, the user may discover that some variables are nevertheless the way they want them (e.g., variable label is 80 characters but the content is not truncated)

This can already be achieved through the varlist() option, but not in a simple way for end users. One would need to capture all variables in a macro, create another macro with the variables to ignore, and then use macro list functions to create a variable list that excludes the ignored variables. Better that labeller commands handle this behind the scenes.

Commands concerned

• lbl_assert_no_long_varlbl
• lbl_assert_var_have_lbl

[kbjarkefur]

Save to char meta data such that information can be used by user downstream