remove old deprecated commands

[amtoine]

Description

in this PR i propose to remove the following old deprecated commands

• hash base64 -> encode base64
• math eval -> math <sub>
• str to-datetime -> into datetime
• str to-decimal -> into decimal
• str find-replace -> str replace
• str to-int -> into int
• keep -> take
• match -> find
• nth -> select
• pivot -> transpose
• unalias -> hide
• all? -> all
• any? -> any
• empty? -> is-empty
• build-string -> str join / string concatenation with +
• str lpad -> fill
• str rpad -> fill
• str collect -> str join
• old-alias -> alias

so old i do not remember them at all 😮

i left the following four commands because they have been moved much more recently i think!

• fetch -> http get
• post -> http post
• benchmark -> timeit
• let-env
• date format -> format date

User-Facing Changes

Tests + Formatting

• 🟢 toolkit fmt
• 🟢 toolkit clippy
• ⚫ toolkit test
• ⚫ toolkit test stdlib

After Submitting

[fdncred]

I still miss pivot. It was so much easier to type.

[sophiajt]

@fdncred maybe we need one called turn or rotate :D

[sholderbach]

Let's go ahead with this! In my view this is not a breaking change as it doesn't affect behavior we advertise as working.

[amtoine]

after the merge with the date format change i've just

• removed the old-alias command which i forgot
• left the date format -> format date deprecation as it's so recent
• renamed LetEnvDeprecated to LetEnv
• moved LetEnv and DateFormat to the "deprecated" section of default_context.rs

[fdncred]

Thanks