Fixed redirection from hisotry server on a proxy

[DanielAronovich]

Bug issue:
#13

Why it happened:

1. The getProxyBasePath function:
   This implementation assumes that "/dataflint" is always the last meaningful part of the URL before the specific application details. However, in a proxy setup, there might be additional path segments between the host and "/dataflint", such as "/gateway/sparkhistory".

2. The onHistoryServerClick function:
   This implementation uses BASE_PATH, which is likely a constant defined elsewhere in the application. The issue here is that BASE_PATH might not include the proxy-specific path segments (like "/gateway/sparkhistory") that are necessary to correctly construct the history server URL in a proxy setup.

Changes:

1. getProxyBasePath function:

   • Uses a regex //history/[^/]+/dataflint/?$/ to match and remove '/history/[app-id]/dataflint/' from the end of any URL.
   • Correctly handles complex proxy setups by preserving everything before this pattern.
   • Example: "http://knox.local:8080/gateway/sparkhistory/history/[app-id]/dataflint" becomes "http://knox.local:8080/gateway/sparkhistory".

2. onHistoryServerClick function:

   • Doesn't rely on BASE_PATH, avoiding issues with incorrect constant values.
   • Uses getProxyBasePath() to dynamically determine the correct base URL.
   • Adapts to both proxy and non-proxy environments without configuration changes.