Web UI: patch 520, 401, 518, 514, and additional small issues

[ylei-tsubame]

This PR patches:

• 6d878e8eb015426b002b5067b6fe8c7bd312ed8e..a7709df2a61fde9facfad6aef6af92a218b7ce78 - Disable touching sessions to prevent accumulating session records; closes #520
• 5ae128bcf4234e348394db708eec2d989616d94c - migrate to modern way of parsing numbers from config variables
• 5550d6131c8a3d5b7a7b18200acccee3e7f453be - Add redirection for when authenticated user accesses /login or /init
• 35469d28956dfca09cb1fbff657e6674e5bfd830 - Prevent browsers from loading cached version upon resuming last opened tabs; closes #401
• cb395fe1ac915c5fe8cd308786e79dfdfd5e1b5a - Set network mapping flag back to 0 on successful form submission; closes #518
• af3ab2989ac4498cf64d313e80d7e5a14b6b28e5..34bd441c837a1f79426349f7e7b4dd0fac3ec8f1 - Reorganize cookies and add react hook for setting redirect when user session expires; closes #514