feat: add chromedriverExecutableDir and autodownload support

[KazuCocoa]

Closes #43
cc @jlipps

[KazuCocoa]

@jlipps maybe we could create 0.3.0 with this.

[jlipps]

it's now published.

[Jiyvn]

@KazuCocoa @jlipps autodownload not work on my side

appium server --allow-insecure chromedriver_autodownload
lgtv2019.log

[KazuCocoa]

Because the embedded browser did not respond what chrome version the device needed. This implementation cares https://github.com/headspinio/appium-lg-webos-driver/pull/48/files#diff-9dd24cf3101d02ce31204899de7beaa39759860d491e54541dcc55c10ec2ae32R37-R117 cases, but not sure what chromedriver should be used for your device case.

WebKit-Version":"537.36 is very common value as the device so it does not help to guess necessary chromedriver. What we could do here is return better error message for this "User-Agent":"" case.

�[38;5;48m[WebOSDriver]�[0m Waiting for app launch to take effect
�[38;5;48m[WebOSDriver]�[0m Waiting for app launch to take effect
�[38;5;48m[WebOSDriver]�[0m The response of http://192.168.10.187:9998/json/version was {"Browser":"","Protocol-Version":"1.1","User-Agent":"","WebKit-Version":"537.36 (@fa89da905405aab455e0f0d4ec7f49631c7ca70b)"}
�[38;5;80m[Chromedriver@b2fd]�[0m Changed state to 'starting'
�[38;5;80m[Chromedriver@b2fd]�[0m Using the static Chromedriver->Chrome mapping
�[38;5;80m[Chromedriver@b2fd]�[0m The most recent known Chrome version: 123.0.6312
�[38;5;80m[Chromedriver@b2fd]�[0m Found 0 executables in '/Users/jiyvn/aviu/apps/lgtv/chromedriver/'

[KazuCocoa]

#50 to return better error message as no info to guess necessary chromedriver version