feat: add and return spaces's colors from skins table

[wa0x6e]

Toward https://github.com/snapshot-labs/workflow/issues/275

This PR adds a new table to hold a space's skin custom colors.

Context

Instead of having each space use a pre-defined skin, we're moving to each space having its own skin. This allow each space to customize its own skin, directly via its space settings

Create table with

CREATE TABLE skins (
  id VARCHAR(100) NOT NULL,
  bg_color VARCHAR(6) DEFAULT NULL,
  link_color VARCHAR(6) DEFAULT NULL,
  text_color VARCHAR(6) DEFAULT NULL,
  content_color VARCHAR(6) DEFAULT NULL,
  border_color VARCHAR(6) DEFAULT NULL,
  heading_color VARCHAR(6) DEFAULT NULL,
  primary_color VARCHAR(6) DEFAULT NULL,
  header_color VARCHAR(6) DEFAULT NULL,
  PRIMARY KEY (id)
);

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 67 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/graphql/helpers.ts	0.00%	42 Missing ⚠️
src/graphql/operations/follows.ts	0.00%	5 Missing ⚠️
src/graphql/operations/proposal.ts	0.00%	5 Missing ⚠️
src/graphql/operations/proposals.ts	0.00%	5 Missing ⚠️
src/graphql/operations/subscriptions.ts	0.00%	5 Missing ⚠️
src/graphql/operations/votes.ts	0.00%	5 Missing ⚠️

Additional details and impacted files

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