Move templates to api directory

In order to access templates while running API from python
package, move `templates` to `api` directory.
Update `pyproject.toml` to include `api/templates` directory
to the python package.
Update `api.user_manager` to use `PackageLoader` to load
templates from the python package.

Signed-off-by: Jeny Sadadia <[email protected]>

Author: Jeny Sadadia

templates/email-verification-successful.jinja2 api/templates/email-verification-successful.jinja2

@@ -30,7 +30,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self._email_sender = None
         self._template_env = jinja2.Environment(
-            loader=jinja2.FileSystemLoader("./templates/")
+            loader=jinja2.PackageLoader("api", "templates")
         )
 
     @property

templates/email-verification.jinja2 api/templates/email-verification.jinja2

@@ -51,8 +51,8 @@ Documentation = "https://kernelci.org/docs"
 Repository = "https://github.com/kernelci/kernelci-api"
 
 [tool.setuptools]
-packages = ["api", "scripts", "templates"]
+packages = ["api", "scripts", "api.templates"]
 
 [tool.setuptools.package-data]
 scripts = ["*"]
-templates = ["*.jinja2", "*.html"]
+"api.templates" = ["*.jinja2", "*.html"]