Remove date-string conversion functions

The strdate_to_datetime and datetime_to_strdate are unused
after removing the Regridders module. Additionally, their funcitonality
is contained within the Dates package with Dates.format and
DateFormats.

docs/src/timemanager.md

@@ -8,8 +8,6 @@ functions from Julia's [Dates](https://docs.julialang.org/en/v1/stdlib/Dates/) m
 
 ```@docs
 ClimaCoupler.TimeManager.current_date
-ClimaCoupler.TimeManager.strdate_to_datetime
-ClimaCoupler.TimeManager.datetime_to_strdate
 ClimaCoupler.TimeManager.trigger_callback
 ClimaCoupler.TimeManager.AbstractFrequency
 ClimaCoupler.TimeManager.Monthly

src/TimeManager.jl

@@ -10,8 +10,6 @@ import Dates
 import ..Interfacer
 
 export current_date,
-    strdate_to_datetime,
-    datetime_to_strdate,
     trigger_callback,
     AbstractFrequency,
     Monthly,
@@ -33,31 +31,6 @@ Return the model date at the current timestep.
 """
 current_date(cs::Interfacer.CoupledSimulation, t::Real) = cs.dates.date0[1] + Dates.Second(t)
 
-"""
-    strdate_to_datetime(strdate::String)
-
-Convert from String ("YYYYMMDD") to Date format,
-required by the official AMIP input files.
-
-# Arguments
-- `strdate`: [String] to be converted to Date type
-"""
-strdate_to_datetime(strdate::String) =
-    Dates.DateTime(parse(Int, strdate[1:4]), parse(Int, strdate[5:6]), parse(Int, strdate[7:8]))
-
-"""
-    datetime_to_strdate(datetime::DateTime)
-
-Convert from Date to String ("YYYYMMDD") format.
-
-# Arguments
-- `datetime`: [Dates.DateTime] object to be converted to string
-"""
-datetime_to_strdate(datetime::Dates.DateTime) =
-    string(lpad(Dates.year(datetime), 4, "0")) *
-    string(string(lpad(Dates.month(datetime), 2, "0"))) *
-    string(lpad(Dates.day(datetime), 2, "0"))
-
 """
     AbstractFrequency
 

test/time_manager_tests.jl

@@ -38,16 +38,6 @@ for FT in (Float32, Float64)
     end
 end
 
-@testset "test strdate_to_datetime" begin
-    @test TimeManager.strdate_to_datetime("19000101") == Dates.DateTime(1900, 1, 1)
-    @test TimeManager.strdate_to_datetime("00000101") == Dates.DateTime(0, 1, 1)
-end
-
-@testset "test datetime_to_strdate" begin
-    @test TimeManager.datetime_to_strdate(Dates.DateTime(1900, 1, 1)) == "19000101"
-    @test TimeManager.datetime_to_strdate(Dates.DateTime(0, 1, 1)) == "00000101"
-end
-
 @testset "trigger_callback" begin
     FT = Float64
     date0 = date = Dates.DateTime("19790321", Dates.dateformat"yyyymmdd")