Add the ability to cherry-pick disable non-essential features#576

Some of the things that are generated in the final script may be unnecessary or unused in some cases. Although setting `BASHLY_ENV=production` removes *some* of the development-oriented features, there are other features that can still be considered dead weight, as was raised in #575. Perhaps adding a single `disable` setting that accepts an array of strings can be used to tweak these features. These are the candidates: #### Deps array (`disable.deps_array`) ```bash declare -A deps=() ``` #### Header comment (`disable.header_comment`) ```bash # This script was generated by bashly 1.2.4 (https://bashly.dannyb.co) # Modifying it manually is not recommended ``` #### Bash3 bouncer (`disable.bash3_bouncer`) ```bash if [[ "${BASH_VERSINFO:-0}" -lt 4 ]]; then printf "bash version 4 or higher is required\n" >&2 exit 1 fi ``` #### Inspect Args function (`disable.inspect_args`) ```bash inspect_args() { ... } ``` #### View markers (`disable.view_markers`) ```bash # :command.version_command <-- this type of comment version_command() { ... } ```