plots: update templates schemas, new smooth

[pared]

Decided to update schema values for our templates, since we already use vega 5.0 in our HTML scripts.
While I was at it I decided to finish iterative/dvc#6438
New smoothing template borrows interactive choice of focused point from our default template.
Added signal that changes smoothing value.

Used following script to generate image:

#!/bin/bash

set -exu
pushd $TMPDIR

wsp=test_wspace
rep=test_repo

rm -rf $wsp && mkdir $wsp && pushd $wsp
main=$(pwd)

mkdir $rep && pushd $rep

git init
dvc init 

git add -A
git commit -am "init"

echo -e "from random import random
import json

result = []
for i in range(1, 100):
	result.append({'val': 1/i + random()/10})
with open('file.json', 'w') as fobj:
	json.dump(result, fobj)
" > train.py

dvc run -d train.py --plots file.json -n train python train.py

git add -A
git commit -am "first"

dvc repro -f
dvc plots diff --targets file.json --template smooth

Old template

New template

[codecov-commenter]

Codecov Report

Merging #40 (73f8a3a) into main (369396f) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #40   +/-   ##
=======================================
  Coverage   95.68%   95.68%           
=======================================
  Files          14       14           
  Lines         464      464           
  Branches       76       76           
=======================================
  Hits          444      444           
  Misses         15       15           
  Partials        5        5           

Impacted Files	Coverage Δ
src/dvc_render/vega_templates.py	97.95% <ø> (ø)

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