web_server support for v3

[RFDarter]

What does this implement/fix?

Adds support for the verison 3 of the web_server.
The js file would need to be hosted at
https://oi.esphome.io/v3/www.js

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Example entry for config.yaml:

esphome:
  name: simple

esp32:
  board: esp32dev
  framework:
    type: arduino

logger:
  level: DEBUG

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

web_server:
  version: 3

button:
  - platform: template
    name: My Button

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (061d5b4) 53.71% compared to head (4c80887) 53.71%.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #6203   +/-   ##
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  Coverage   53.71%   53.71%           
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  Files          50       50           
  Lines        9404     9404           
  Branches     1653     1653           
=======================================
  Hits         5051     5051           
  Misses       4055     4055           
  Partials      298      298           

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[jesserockz]

Approved pending merge/release of webserver code