feat: Parameter update delay at specific block height

[rbajollari]

Description

closes: #96

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[codecov-commenter]

Codecov Report

Merging #243 (f88b32c) into main (cc615f6) will decrease coverage by 0.26%.
Report is 1 commits behind head on main.
The diff coverage is 16.66%.

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@@            Coverage Diff             @@
##             main     #243      +/-   ##
==========================================
- Coverage   18.79%   18.53%   -0.26%     
==========================================
  Files          51       53       +2     
  Lines       12277    12907     +630     
==========================================
+ Hits         2307     2392      +85     
- Misses       9839    10392     +553     
+ Partials      131      123       -8     

Files Changed	Coverage Δ
x/oracle/types/keys.go	85.71% <0.00%> (-6.60%)	⬇️
x/oracle/types/plan.go	0.00% <0.00%> (ø)
x/oracle/types/oracle.pb.go	0.50% <0.43%> (-0.01%)	⬇️
x/oracle/types/tx.pb.go	0.64% <0.58%> (-0.01%)	⬇️
x/oracle/types/msgs.go	68.46% <15.00%> (+19.04%)	⬆️
x/oracle/types/proposal.go	25.00% <16.66%> (-8.34%)	⬇️
x/oracle/keeper/msg_server.go	66.66% <52.63%> (+3.57%)	⬆️
x/oracle/types/params.go	78.74% <61.70%> (-0.97%)	⬇️
x/oracle/keeper/param_update_plan.go	96.66% <96.66%> (ø)
x/oracle/abci.go	81.10% <100.00%> (+0.93%)	⬆️

... and 2 files with indirect coverage changes

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[adamewozniak]

@zarazan please review 🙏

[zarazan]

I like that this makes the code cleaner in some spots.