env-manager: ui polish (#127)

* env-manager: migrate to pico 2.0.6

* env: option to hide children from ui

* introduce template hierarchy

* style: improve menu styling

* env: reorganize tasks, pull before install

---------

Co-authored-by: Giorgi Lekveishvili <lekva@gl-mbp-m1-max.local>
diff --git a/core/installer/welcome/static/main.css b/core/installer/welcome/static/main.css
index 1b6ec68..2a01ae8 100644
--- a/core/installer/welcome/static/main.css
+++ b/core/installer/welcome/static/main.css
@@ -1,26 +1,29 @@
 [data-theme="light"],
 :root:not([data-theme="dark"]) {
-	--font-family: Hack, monospace;
-	--font-size: 14px;
-	--background-color: #d6d6d6;
-	--border-radius: 0;
-	--form-element-border-color: #ffffff;
-	--form-element-active-border-color: #7f9f7f;
-	--primary: #7f9f7f;
-	--primary-hover: #d4888d;
-	--grid-spacing-horizontal: 0;
+	--pico-font-family: Hack, monospace;
+	--pico-font-size: 14px;
+	--pico-background-color: #d6d6d6;
+	--pico-border-radius: 0;
+	--pico-form-element-border-color: #ffffff;
+	--pico-form-element-active-border-color: #7f9f7f;
+	--pico-primary: #7f9f7f;
+	--pico-primary-background: #7f9f7f;
+	--pico-primary-hover: #d4888d;
+	--pico-primary-hover-background: #d4888d;
+	--pico-grid-spacing-horizontal: 0;
 }
 
 input[type="checkbox"] {
-	--form-element-border-color: #3a3a3a;
+	--pico-form-element-border-color: #3a3a3a;
 }
 
 main.container {
 	max-width: 850px;
+	margin-top: 13rem;
 }
 
 .dodo {
-	font-size: 2.5rem;
+	font-size: 1.6rem;
 	font-weight: bold;
 	background-color: #3a3a3a;
 	border-left: 1px dashed #3a3a3a;
@@ -32,12 +35,13 @@
 
 #menu {
 	border-bottom: 1px dashed #3a3a3a;
+	padding-left: 5rem;
+	padding-right: 5rem;
 }
 
 #menu a {
-	font-size: 1.4rem;
+	/* font-size: 1.2rem; */
 	color: #3a3a3a;
-	border-right: 1px dashed #3a3a3a;
 }
 
 #menu li {
@@ -45,6 +49,14 @@
 	padding-bottom: 0;
 }
 
+#links {
+	--pico-nav-element-spacing-horizontal: 3rem;
+}
+
+#menu li {
+	border-right: 1px dashed #3a3a3a;
+}
+
 div.contents-header {
 	font-size: 1.2rem;
 	border-width: 1px;
@@ -56,6 +68,10 @@
 	border-style: none solid solid solid;
 }
 
+main > div.grid {
+	--pico-grid-column-gap: 0;
+}
+
 div.contents-header > div {
 	padding: 1rem 3rem;
 }
@@ -65,7 +81,8 @@
 }
 
 #create-instance-form {
-	--spacing: 10px;
+	--pico-spacing: 10px;
+	/* TODO(gio): figure out why overriding --pico-background-color does not work */
 	background-color: #3a3a3a;
 }
 
@@ -75,6 +92,7 @@
 
 #create-instance-form input, textarea, button {
 	border-width: 0.5px !important;
+	background-color: #3a3a3a;
 }
 
 #create-instance-form input {