fix(tenantName): remove invalid characters from tenant name

[Phil91]

Description

• check for invalid characters in company name when creating the tenant, if existing remove those.
• use only the bpn for the the subdomain when creating the subAccount

Why

The sap wallet only accepts letters, digits and hyphens (not at the start or end)

Issue

Refs: #86 #87

Checklist

• I have performed a self-review of my own code
• I have successfully tested my changes locally
• I have added tests that prove my changes work
• I have checked that new and existing tests pass locally with my changes
• I have commented my code, particularly in hard-to-understand areas
• I have added copyright and license headers, footers (for .md files) or files (for images)