Allow empty virtual directory

[KharchenkoMaks]

Fix double slashes in paths when virtualDir is set to root

Closes #7

Issue

Setting virtualDir: / or virtualDir: "" to deploy WProofreader at the root path caused malformed double-slash paths in probe definitions and the post-install notes URL, because .Values.virtualDir was interpolated directly into strings that already contained surrounding
slashes.

Solution

Added a single reusable helper wproofreader.virtualDirBasePath to _helpers.tpl that normalizes virtualDir into a consistent path prefix:

• "wscservice" → "/wscservice"
• "/" or "" → "" (empty string)

This allows all call sites to append their path suffix directly without any per-use-case branching:

{{ include "wproofreader.virtualDirBasePath" . }}/api?cmd=status
-> "/wscservice/api?cmd=status"  (default)
-> "/api?cmd=status"             (root)

Changes

File	Change
templates/_helpers.tpl	Added wproofreader.virtualDirBasePath helper
templates/deployment.yaml	Liveness and readiness probe paths now use the helper
templates/NOTES.txt	Base URL construction now uses the helper
values.yaml	Replaced WPR_DOMAIN_NAME example by WPR_JVM_MAX_MEMORY_SIZE_MB

Notes

• The WPR_VIRTUAL_DIR env var passed to the container is intentionally not normalized — the container accepts / and "" natively.
• All existing deployments with the default virtualDir: wscservice are unaffected.