feat: adding generate embed url functionality

[LukaFontanilla]

Description

Should include a concise description of the changes (bug or feature), it's
impact, along with a summary of the solution

This PR adds a new tool to the Looker MCP Toolbox, that enables the user authenticated to the Looker Source to generate authenticated embed urls for dashboards, looks and queries. When combined with other tools that already exist in the Looker toolbox, this enables searching existing content and providing authenticated urls to them OR creating authenticated urls from queries generated via Natural Language. The embed urls will create an embed session for the user and can be opened directly or added to an iframe src attribute to provide a smooth Embedded Analytics setup.

Additionally this PR adds a new optional parameter to the Looker source called SessionLength which an admin setting up the Looker source can set to determine how long the Embed sessions last for.

PR Checklist

Thank you for opening a Pull Request! Before submitting your PR, there are a
few things you can do to make sure it goes smoothly:

• [ X] Make sure you reviewed
  CONTRIBUTING.md
• [ X] Make sure to open an issue as a
  bug/issue
  before writing your code! That way we can discuss the change, evaluate
  designs, and agree on the general idea
• Ensure the tests and linter pass
• [ X] Code coverage does not decrease (if any source code was changed)
• [X ] Appropriate docs were updated (if necessary)
• [ X] Make sure to add ! if this involve a breaking change

🛠️ Fixes #1876 #1876

[LukaFontanilla]

@drstrangelooker are you able to kick off the unit tests for this PR ?

[drstrangelooker]

/gcbrun

[drstrangelooker]

=== RUN   TestParseFromYamlLookerGenerateEmbedUrl/basic_example
    lookergenerateembedurl_test.go:69: incorrect parse: diff   server.ToolConfigs{
          	"example_tool": lookergenerateembedurl.Config{
          		... // 2 identical fields
          		Source:       "my-instance",
          		Description:  "some description",
        - 		AuthRequired: nil,
        + 		AuthRequired: []string{},
          	},
          }
--- FAIL: TestParseFromYamlLookerGenerateEmbedUrl (0.00s)
    --- FAIL: TestParseFromYamlLookerGenerateEmbedUrl/basic_example (0.00s)

[drstrangelooker]

@LukaFontanilla I think you have been added to the collaborators group that can push your branches directly and approve your own unit tests.

edit: yes, you are part of toolbox contributors and so should have access directly to this repo.

[LukaFontanilla]

@LukaFontanilla I think you have been added to the collaborators group that can push your branches directly and approve your own unit tests.

edit: yes, you are part of toolbox contributors and so should have access directly to this repo.

Ok thank you Mike. I can fix the unit test and then kick that off once more

[drstrangelooker]

I fixed the test. Running now.