Block functionapp creation after runtime EOL and warn if within 6 months

[Francisco-Gamino]

Description

The New-AzFunctionApp cmdlet pulls the function app runtime definitions from the Stacks API. Currently, only runtimes that have not reached EOL are available for function app creation. This issue is to update this code path and display a warning when the runtime version is approaching EOL within 6 months.

6 months before EOL:
Upgrade your app to <'Functions'/language runtime> <latest available functions/stack version> as <current functions/stack runtime version> will reach end-of-life on <EOL date> and will no longer be supported. Learn more: aka.ms/FunctionsStackUpgrade.

Example:
Upgrade your app to Node.js 22 as Node.js 18 will reach end-of-life on April 30 2025 and will no longer be supported. Learn more: aka.ms/FunctionsStackUpgrade.

After EOL:
Upgrade your app to <'Functions'/language runtime> <latest available functions/stack version> as <current functions/stack runtime version> has reached end-of-life on <EOL date> and is no longer supported. Learn more: aka.ms/FunctionsStackUpgrade.

Issue script & Debug output

N/A

Environment data

N/A

Module versions

N/A

Error output

N/A

[MadhuraBharadwaj-MSFT]

Action	Condition	Behavior	Error/warning message
Creating a New Function App
	No Functions version and/or stack version is provided	Default to Functions v4 and the latest stack version	N/A
	Provided Functions version and/or stack version is out of support	Block creation with an error message.	"Use Functions/Stack version as <stack/functions runtime version> has reached end-of-life on and is no longer supported. Learn more: aka.ms/FunctionsStackUpgrade"
	Provided Functions version and/or stack version will be out of support in less than 6 months	Allow creation with warning message.	"Use Functions/Stack version as <stack/functions runtime version> will reach end-of-life on and will no longer be supported. Learn more: aka.ms/FunctionsStackUpgrade"
Updating an Existing Function App
	Functions version and/or stack version is out of support	Allow update with warning message.	"Upgrade to Functions/Stack version as <stack/functions runtime version> has reached end-of-life on and is no longer supported. Learn more: aka.ms/FunctionsStackUpgrade"
	Functions version and/or stack version will be out of support in less than 6 months	Allow update with warning message.	"Use Functions/Stack version as <stack/functions runtime version> will reach end-of-life on and will no longer be supported. Learn more: aka.ms/FunctionsStackUpgrade"
Deploying to an Existing Function App
	Functions version and/or stack version is out of support	Allow deployment with warning message.	"Upgrade to Functions/Stack version as <stack/functions runtime version> has reached end-of-life on and is no longer supported. Learn more: aka.ms/FunctionsStackUpgrade"
	Functions version and/or stack version will be out of support in less than 6 months	Allow deployment with warning message.	"Use Functions/Stack version as <stack/functions runtime version> will reach end-of-life on and will no longer be supported. Learn more: aka.ms/FunctionsStackUpgrade"

[Francisco-Gamino]

/cc @amamounelsayed