feat: add bundle.android config to build and sign the apk file in release mode

[fontlos]

Add this to Dioxus.toml

[bundle.android]
jks_file = "path/to/jks file relative to Dioxus.toml"
jks_password = "jks_password "
key_alias = "key_alias"
key_password = "key_password "

When release flag is enabled and this configuration exists at the same time, use gradlew assembleRelease build and sign apk file

[fontlos]

@jkelleyrtp I sincerely apologize for mistakenly pushing the commit to my main branch and creating a pull request. This might have caused some confusion in the Git history. Should I close this PR and create a new branch to submit again?