docs: add "same suffix length" rule for the tag assignments

- The platform automatically distributes users to teams based on the tags (with chosen prefix) of the selected users.

    Let's illustrate this functionality on the following example:

    - Imagine, we have users (trainees) and their tags in the brackets (these tags were assigned via a CSV file):

        - trainee1 (PowerPlantTTX-team1, HealthCareEX-team3)

        - trainee2 (PowerPlantTTX-team1, HealthCareEX-team2)

        - trainee2 in the second team

        - trainee1 and trainee3 in the third

            team

- The following **rules have to be complied with** to make this assignment possible:

    - Prefix parts have to be unique for a given assignment (which can be achieved by making them long

        enough). If we had tags `EXERCISE_t1` and `EX_t1`, and we wanted to use the `EX_t1`, we would

        need to use the prefix `EX`, which would also match with `EXERCISE_t1` and could cause

        incorrect assignment (if we used the prefix `EX_`, we would dodge the match with other tags).

        To simplify, the prefix is checked as a match for the first characters of the tags.

    - Prefix match is case-sensitive.

    - Suffixes can have any values, which can be lexicographically ordered (correct examples where

        `Exercise` or `Exercise-` are the prefix):

        - Exercise-1, Exercise-2, Exercise-3 (those with 1 will be assigned to the first team, those

            with 2 to the second...)

        - Exercise-a, Exercise-b, Exercise-c (those with _a_ will be assigned to first team, those with

            _b_ to second...)

        - Exercise-t1, Exercise-t2, Exercise-t3 (those with _t1_ will be assigned to first team, those

            with _t2_ to second...)

    - _Standardize suffix lengths_ because the system uses lexicographic (text-based) ordering,

        variable-length numbers will cause sorting issues.

        For example, "10" is alphabetically sorted before "2".

        To prevent this, you must zero-pad your digits so all suffixes have the same length.

        - Use `Team-01`, `Team-02`, ... `Team-12`

        - Avoid `Team-1`, `Team-2`, ... `Team-12`

        If you expect 3-digit number of teams, then use `Team-001`, `Team-002`, ..., `Team-100`.

        Continue this pattern (adding more zeros) if you expect even larger numbers.

        _Tip: If you are unsure of the final count, it is safer to over-pad (e.g., use 3 digits even if you only have 50 teams)._

    - If more tags match the prefix than the number of present teams, the operation will fail.

        Either the number of teams has to be increased, users with tags that exceed the number of team

        would need to be removed from selection, or the exceeding tags would need to be removed.

- WARNING: This feature does not work with _role exercise_.

#### **Copy existing assignment**