Update bootstrap, jquery, copyright and local-mainsite link

[TimHess]

also updates site nav to match mainsite as of SteeltoeOSS/MainSite#141

[TimHess]

This PR is now (manually) deployed and paired with the mainsite pr preview site

[bart-vmware]

Menu buttons are still broken. Repro:

• Click "Why Steeltoe" (expands)
• Click it again (bug: does not collapse)
• Click "Get Started" (collapses "Why Steeltoe" and expands "Get Started")
• Click "Why Steeltoe" (bug: now you see both menus)

[bart-vmware]

See remarks. Great job on the deployment work, it's nice to be able to test without running the site locally.

[github-actions]

Preview link: https://docs-steeltoe-pr-310.azurewebsites.net

• Your changes have been deployed to the preview site. The preview site will update as you add more commits to this branch.
• The preview link is shareable, but will be deleted when the pull request is merged or closed.

This is an automated message.

[TimHess]

Looking at #310 (comment), I'm still seeing the following issues:

• Still broken on Docs, works on MainSite: Update bootstrap, jquery, copyright and local-mainsite link #310 (comment)
• Very small browser, open hamburger menu, click Get Started: border around submenu entries is missing. Docs:

vs MainSite:

• Small browser (a bit wider than above), open hamburger menu: Top-level menu entries are left-aligned instead of centered. And the menu now overlays existing content instead of insertion. Docs:

vs MainSite:

The differences are caused by significant interference from docfx here... I can try to fix it now, but I'm not sure how much effort it's worth if we follow up on updating docfx (which I think is something we should do soon)