feat(openebs): poolname input validation

[ksimm1]

Description
Adds input validation to the poolname / dataset variable to prevent users entering common invalid paths

• rejects leading /
• enforces at least one /
• rejects backslash \ in the path
• rejects ix-applications in the path
• rejects TANK or TANK/ entries

AI Summary of regex pattern
In summary, this regex pattern matches strings that:

1. Do not contain a backslash (\) anywhere.
2. Do not contain the substring "ix-applications" anywhere.
3. Start with one or more characters that are not a forward slash (/).
4. Followed by one or more occurrences of a forward slash (/) followed by one or more characters that are not a /.

Here are some examples:

Matching examples:

• hello/world/subdir
• foo/bar/baz/qux
• abc/def/ghi/jkl

Non-matching examples:

• hello\world (contains a backslash)
• ix-applications/anything (contains the substring "ix-applications")
• hello/world/ix-applications (contains the substring "ix-applications")
• /hello/world (starts with a forward slash)

Keep in mind that this regex pattern is quite specific, and it's likely designed to match a specific type of path or directory structure.
⚒️ Fixes #21275

⚙️ Type of change

• [x ] ⚙️ Feature/App addition
• 🪛 Bugfix
• ⚠️ Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 🔃 Refactor of current code

🧪 How Has This Been Tested?
Tested via https://regex101.com/r/8aNdeE/1

📃 Notes:

✔️ Checklist:

• [x ] ⚖️ My code follows the style guidelines of this project
• [x ] 👀 I have performed a self-review of my own code
• #️⃣ I have commented my code, particularly in hard-to-understand areas
• 📄 I have made corresponding changes to the documentation
• ⚠️ My changes generate no new warnings
• 🧪 I have added tests to this description that prove my fix is effective or that my feature works
• [x ] ⬆️ I increased versions for any altered app according to semantic versioning
• [ x] I made sure the title starts with feat(chart-name):, fix(chart-name): or chore(chart-name):

➕ App addition

If this PR is an app addition please make sure you have done the following.

• 🖼️ I have added an icon in the Chart's root directory called icon.png

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