Allow set default convention endpoints behavior

[picodotdev]

Summary of pull request changes:

• Moved RouterDispatcher before PageRender dispatcher to allow configure behavior, ["after:ComponentEvent", "before:PageRender"].
• Added Behavior enum.
• Page without route and page route takes precedence over other route (same as current behavior).
• Index pages can be used, routes can be used in Index pages, non Index pages routes takes precedence.
• Added some test for RouterDispatcher and test route behavior.
• Replaced deprecated request.getContextPath() usages with Symbol(SymbolConstants.CONTEXT_PATH).
• Minor code style changes.

Fixes #8

[picodotdev]

Please review pull request changes and give a try, comments are welcome, I will try to add the necessary changes if any to be accepted if you find this useful.