First stage of creating auth flow

[ej-choi]

• Create various Button components and configs
• Add a sign-in auth page for starting auth flow

I wanted to get these changes committed, as the Stripe integration may be added soon.

The CSS formatting for the HTML elements is not quite right, but I will change them later on (when I've taught myself more about HTML/CSS).

LinkButton/FunctionButton different components so that we can use 'href' or 'onClick' without any conflict.

buttonConfig along with enums and dictionary to delimit and facilitate button customisation and to standardise button usage.

@Firgrep for any comments or improvements, please annotate on the code changes.

[ej-choi]

I'm trying to figure out OAuth/NextAuth currently and how the app remembers what gmail account I've used even when I've cleared the cookies and got rid of database entries. Something for tomorrow/later this week.

And although I have made a commit already, I will clear up some of those html classNames after reading up a bit more on daisyUI docs